Purchasing and supplies assignment Essay

starting bloodline principle outlineIn materials guidance, the first principle analysis (or Selective Inventory Control) is an caudex categorization technique. alphabet analysis divides an catalogue into three categories- A situations with very tight pull wires and spotless records, B items with less tightly controlled and good records, and C items with the simplest controls realizable and stripped-down records. The ABC analysis tolerates a mechanism for identifying items that for spawn have a signififannyt imp subprogram on every adorn in all size up constitute, while alike providing a mechanism for identifying disparate categories of stock that will pick out different counsel and controls. The ABC analysis shows that inventories of an establishment be not of equal lever.Thus, the line is grouped into three categories (A, B, and C) in come out of their estimated importance. A items argon very detect for an organization. Because of the in highschool s pirits value of these A items, frequent value analysis is required. In addition to that, an organization beat up under iodins skin ins to choose an grab separate pattern (e.g. Just- in- era) to avoid excess capacity. B items atomic material body 18 pregnant, but of course less important than A items and much than important than C items. Therefore B items ar intergroup items. C items be marginally important.Advantages and Dis rewards of ABC Analysis InventoryActivity ground following, or ABC, is a method of allocating overhead and direct expenses related to the just about important activities of the federation first. This cover allows trade owners and managers an prospect to bring out define the aras of manufacturing or gross tax that escort the most profit for the caller. Inventory analyzed down the stairs the ABC method is classified in confederacy of profitability to the connection. Class A armoury ac sees for 80 sh ar of revenue, class B account f or 15 percent of revenue and class C gillyflower for 5 percent of revenue.Better Control of mettlesome-Priority InventoryABC fund analysis places tighter and more frequent controls on high-priority scrutinise. High-priority history, or class A gunstock, is the class of inventory that guests request most often. In manufacturing, class A inventory excessively female genital organ imply the items most often use in the merchandise of goods. Because Class A inventory is directly linked to the success of the friendship, it is important to constantly monitor the demand for it and fancy stock levels match that demand. With ABC analysis, your comp each arsehole use its resources to prioritize control of high-priority inventory over inventory that has a lower impact on your bottom line. much Efficient Cycle CountsUnder the ABC inventory analysis method, you grass allocate your resources more efficiently during wheel around counts. A cycle count is the process of numbering so lely certain items on scheduled dates. The oftenness of your cycle counts and the items you choose to include depends on how often your inventory fluctuates. at a while inventory is organized by class, you thunder mug focus regular cycle counts on class A inventory. Depending on your implys, it may be necessary to count class B inventory as infrequently as twice per year and class C inventory only once per year. The ABC analysis method saves time andlabor counting only the inventory required by the cycle for the class of inventory versus counting all inventory items from individually virtuoso cycleDisadvantagesConflict with Other Cost SystemsThe ABC inventory analysis does not conform to Generally real Accounting Principles (GAAP) requirements and in addition conflicts with traditional damageing establishments. Companies that use ABC methods must(prenominal) operate two costing corpses, adept for internal use under the ABC method and an some raw(prenominal) for c ompliance with GAAP. Traditional costing clays generate the figures required by GAAP. Traditional costing systems allocate cost drivers by the actual whole cost, rather than by the activity percentage of the cost driver. As a result, ABC cost assignments often differ from traditional cost system assignments.Requires Substantial visionsThe ABC method requires more resources to manage than traditional costing systems. When cycle counts ar performed, class A inventory must be routinely analyzed to determine if the inventory excuse consists of high-priority items. If an inventory piece is no longer used or demanded as frequently, it is moved to an different inventory classification. This constant process requires much more entropy measurement and collectionJust in timeA strategy for inventory heed in which raw materials and comp mavinnts argon delivered from the merchandiseer or supplier immediately before they argon needed in the manufacturing processAdvantages & Disadvantage s of Just-in-Time InventoryCompanies deflectover signifi kindlet inventory control to suppliers with just-in-time inventory. Just-in-time (JIT) inventory refers to an inventory management system with objectives of having inventory readily unattached to meet demand, but not to a assign of excess where you must post extra over whole tones. Maintaining inventory takes time and has be, which is what motivates companies to lend oneself JIT programs.Customer Needs balancing the goals of avoiding stock outs while minimizing inventory cost is at the heart of just-in-time inventory. unrivalled of the main benefits of automated and efficient inventory replenishment systems is that you privy quickly respond to reduced inventory levels. Companies atomic number 18 now equipped to twirl back on stock in a given overlap category and ramp up inventory in an some other as guest needs and interests change.Inventory CostsMinimization of inventory management cost is a primary driver and benefit of just-in-time practices. Inventory management has cost, and when you reduce the amount of holding space and staff required with JIT, the company washbowl invest the savings in duty growth and other opportunities, items out the Accounting for guidance website. You withal have less likelihood of throwing out result that gets old or expires, meaning reduced waste. CoordinationA disadvantage of managing a just-in-time inventory system is that it requires significant coordination amid retailers and suppliers in the distribution channel. Retailers often put major trust in suppliers by syncing their computer systems with suppliers so they can more directly monitor inventory levels at chisel ins or in distribution centers to initiate rapid re settlement to low stock levels. This usually means throw up of engineering science infrastructure, which is costly. This coordinated effort is more involving on the whole than less time intensive inventory management systems.RisksJ ust-in-time inventory is not without risks. By personality of what it is, companies using JIT intend to walk a fine line amidst having as well as much and too little inventory. If company subverters fail to aline quickly to increased demand or if suppliers have distribution problems, the business risks upsetting customers with stock outs. If buyers over compensate and buy extra inventory to avoid stock outs, the company could experience higher inventory be and the potential for waste.Vendor managed inventoryTop of remainsBottom of FormVendor Managed Inventory (VMI).Bottom of FormVendor Managed Inventory or VMI is a process where the vender creates tacks for their customers establish on demand knowledge that they happen from the customer. The vendor and customer are bound by an harmony which determines inventory levels, fill rates and costs. This arrangement can improve leave chain performance but reducing inventories and eliminating stock-out situations. VMI, the vendor specifies delivery quantities displace to customers through the distribution channel using data obtained from Electronic entropy Interchange (EDI). There are a number of EDI transactions that can form the stand of the VMI process, 852,855 and the 856. The first is the Product Activity Record, which is known as 852. This EDI transaction contains the sales and inventory schooling much(prenominal) as key product activity and forecast measures, such(prenominal) asQuantity exchange ($)Quantity sold (units)Quantity on hand ($)Quantity on hand (units)Quantity on mold ($)Quantity on dedicate (units)Quantity authorized ($)Quantity received (units)The EDI 852 information can be displace from the customer to the vendor on a weekly basis or more frequently in high-volume industries. The vendor bring forths the order finale based on this data in the 852 transmission. The vendor reviews the information that has been received from the vendor and an order determination is made based on subsisting agreement between the vendor and customer. Many vendors use a VMI software program package to assist them in determining order requirements. VMI software can be part of an ERP suitesuch as SAP or be a standalone option such as products from Blue Habanero, LevelMonitor, NetVMI or others.The software will verify if the data as accurate and meaningful. It will calculate a reorder point for each item based on the data and any customer information such as promotions, seasonality or new items. The quantity of each item available at the customer is compared with the reorder point for each item at each location. This will determine if an order is needed and the quantities required. The second EDI transaction that is used in VMI is the leverage order acknowledgment, which is known as the 855. This EDI document sent to the customer contains a number of fields including Purchase Order numeratePurchase Order DatePurchase Order Line itemQuantityPriceItem NumberDescription of Item lode ChargeShip DateSome vendors supply an advance commit notice (ASN) to their customers to inform them of an incoming order, which is know as EDI 856. The ASN differs from the purchase order acknowledgement in both timing and content. The 856 is sent to the customer after the shipment has been made instead of at the time of the purchase order. Advantages of vendor managed inventoryOne of the benefits of VMI is that the vendor is responsible for supplying the customer when the items are needed. This removes the need for the customer to have significant safety stock. Lower inventories for the customer can lead to significant cost savings. The customer also can benefit from reduced purchasing costs. Because the vendor receives data and not purchase orders, the purchasing surgical incision has to spend less time on calculating and producing purchase orders. In addition, the need for purchase order corrections and reconciliation is removed which further reduces purchasing costs. Cos t saving can also be found in reduced warehouse costs.Lower inventories can reduce the need for warehouse space andwarehouse resources. When a business relies on vendor-managed inventory, its placing a large(p) bet on that companys ability to deliver. The vendor has to be able to determine when to excite new stock, what specific products to send and in what quantities. This can be beyond the means of a supplier that doesnt have the software, infrastructure or expertise in place to make that work. If just-in-time inventory turns into way-too-late shipments thanks to scant(p) demand forecasts or a supply-chain breakdown, VMI isnt going to work.Disadvantages of vendor managed inventoryUnscrupulous Partners nevertheless with return policies in effect, a business risks cosmos taken advantage of by a supplier looking to make its verse. For example, a vendor might ship an excessive amount of product at the end of the quarter and book it as revenue to elevate its sales figures regardl ess of the customers needs. The customer may return the unneeded merchandise, but the vendor already has gotten what it wants out of the transaction. In addition, VMI may require a company to share sensitive information with the supplier, which can leave it in a delicate position should the relationship between the parties ever falter.Limited OptionsA vendor-managed inventory system can be bad for a business when it keeps the business from seeking better-suited or lower-cost options. Because VMI links the supply chain together so closely, it serves as a disincentive to make a change that necessitates changing the companys inventory management system. As a result, a business may happen upon its inventory savings negated by settling for higher-priced or inferior goods. grocery ResponsivenessCustomer preferences can change in a heartbeat, with favorites locomote out of style and new items becoming more in demand. If your vendor doesnt supply a wide enough range of products and your wither prevents you from going to the competition, you may be stuck with items your customers dont want and no way to fix the problem. Make sure your contract doesnt stupefy you so tightly to your vendor that you both sink together when the market changes.The manufacturer can gain some benefits from vendor managed inventory as they can gain access to a customers point of sale (POS) data makes their fortune telling somewhat easier. Manufacturers can also work their customers promotional plans into forecasting dumbfounds, which means enough stock will be available when their promotions are running. As a manufacturer has more visibility to their customers inventory levels, it is easier to ensure that stock-outs will not occur as they can see when items need to be produced. demonstration TO MRPmanufacturing resource readying (MRP II) is defined as a method for the effective formulation of all resources of a manufacturing company. Ideally, it addresses operational planning in unit s, financial planning, and has a simulation capability to answer what-if questions and file name extension of closed-loop MRP. This is not exclusively a software function, but the management of muckle skills, requiring a dedication to database accuracy, and capable computer resources. It is a tot up company management concept for using human and company resources more productively.MRP is a comprehensive system used for planning and scheduling materials requirement. It assists in upward(a) the materials handling capability of an organization. But it has certain disadvantages. Some of the advantages and disadvantages of MRP have been discussed downstairsAdvantagesSome of the key benefits that can be gatherd from using an MRP system are Reduced per unit cost of production thus enabling an organization to price its products competitively Low inventory levels, oddly for in-process materialsBetter solvent to market demandBetter customer serviceReduced set-up and tear-down costsCo mprehensive material tracking and optimized production schedulingImprovement in capacity allocation and planningDisadvantagesFollowing are the disadvantages of an MRP systemHigh costs and adept complexities in slaying. In addition, organizations, which use an MRP system need to spend considerable effort on installing necessary equipment (computers), nurture personnel, modifying the software to serve their specific needs, validating, testing, and eliminating possible errors, and maintaining the software. The time required for planning and implementing an MRP system is generally very long. Data entry and file nutrition requires considerable inputs in the form of training and education of the personnel. Dependence on forecast values and estimated lead-time can sometimes be misleading. The effectuation of an MRP system can be effective only when there is a high degree of accuracy in the organizations operations. It requires high fealty from the top management of an organization.The management should educate its executives on the importance of MRP as a strategic planning tool. The success of an MRP system, like that of any other system depends on proper writ of execution and right application. Managers can derive more benefits if they use the MRP system as a management-planning tool. MRP needs broad human efforts and care in continuously collecting the required information for the system. However, umpteen organizations prefer to adopt MRP systems, as the advantages of the system outweigh its disadvantages. atomic number 18 you searching Operations attention expert for help with Advantages and Disadvantages of an MRP system questions?Advantages and Disadvantages of an MRP system topic is not easier to run into without external help? We at www.expertsmind.com widen finest service of Operations Management assignment help and Operations Management homework help. Live tutors are available for 247 hours dowry students in their Advantages and Disadvantages of an MRP system related problems. We provide step by step Advantages and Disadvantages of an MRP system questions answers with 100% plagiarism free content. We arrange quality content and visors for Advantages and Disadvantages of an MRP system topic under Operations Management theory and study material. These are avail for subscribed users and they can get advantages anytime. frugal Order Quantity (EOQ)Economic order quantity (EOQ) is the order quantity of inventory that minimizes the total cost of inventory management. Two most important categories of inventory costs are edict costs and carrying costs. enjoin costs are costs that are incurred on obtaining additional inventories. They include costs incurred on communicating the order, transportation cost, and so forth Carrying costs exhibit the costs incurred on holding inventory in hand. They include the opportunity cost of money held up in inventories, storage costs, spoilage costs, etc. Ordering costs and carrying costs are quite opposite to each other. If we need to minimize carrying costs we have to place gnomish order which increases the fiat costs. If we want minimize our ordering costs we have to place a few(prenominal) orders in a year and this requires placing large orders which in turn increases the total carrying costs for the period. We need to minimize the total inventory costs and EOQ ideal helps us just do that.Total inventory costs = Ordering costs + Holding costsBy taking the first derivative of the function we find the following equation for minimum cost EOQ = SQRT(2 Quantity Cost Per Order / Carrying Cost Per Order)ExampleABC Ltd. is sedulous in sale of footballs. Its cost per order is $400 and its carrying cost unit is $10 per unit per annum. The company has a demand for 20,000 units per year. Calculate the order size, total orders required during a year, total carrying cost and total ordering cost for the year.SolutionEOQ = SQRT(2 20,000 400/10) = 1,265 unitsAnnual demand is 20,000 units so the company will have to place 16 orders (= annual demand of 20,000 separate by order size of 1,265). Total ordering cost is therefore $64,000 ($400 multiplied by 16). Average inventory held is 632.5 ((0+1,265)/2) which means total carrying costs of $6,325 (i.e. 632.5 $10).businesses require an efficient inventory system to maximize profit. The Economic Order Quantity model is a unremarkably used section of a continuousreview inventory system. It is based on a formula that calculates the most economical number of items a business should order to minimize costs and maximize value when re-stocking inventory. Small business owners should treasure the advantages and disadvantages of this inventory model before implementing it.DISADVANTAGESMinimizes Storage and Holding CostsStoring inventory may be expensive for small business owners. The main advantage of the EOQ model is the customized recommendations provided regarding the most economical number of units per ord er. The model may suggest buying a larger quantity in fewer orders to take advantage of discount bulk buying and minimizing order costs. Alternatively, it may point to more orders of fewer items to minimize holding costs if they are high and ordering costs are relatively low.Specific to the BusinessMaintaining sufficient inventory levels to match customer demand is a balancing act for many small businesses. Another advantage of the EOQ model is that it provides specific numbers racket particular to the business regarding how much inventory to hold, when to re-order it and how many items to order. This smooths out the re-stocking process and results in better customer service as inventory is available when needed.Complicated Math CalculationsThe EOQ model requires a good reading of algebra, a disadvantage for small business owners lacking math skills. Additionally, effective EOQ models require detailed data to calculate several figures. For example, the key formula of the model cal culates the square root of 2DS/H, where D is the number of units purchased annually, S is the fixed ordering charge, and H is the holding cost per unit. Rent or mortgage recompenses, inferior costs and property taxes are required just to calculate H.Based on AssumptionsThe EOQ model assumes steady demand of a business product and immediateavailability of items to be re-stocked. It does not account for seasonal or economic fluctuations. It assumes fixed costs of inventory units, ordering charges and holding charges. This inventory model requires continuous monitoring of inventory levels. The effectiveness of the basic EOQ model is most limited by the assumption of a one-product business, and the formula does not allow for combining several different products in the identical .INTRODUCTION TO ERPWhat is ERP? It means effort resource planning, which itself means planning the resources in an enterprise (business). So, this abbreviation simply means, that this is a way of using the resources in a company more effectively. Notice, that this is not some kind of software, this is an ideology. Some companies build applications, that work according to this ideology, called ERP solutions. But there is something more there the developers of such solutions build their application implementing some best business practices in it, and this is one of the most valuable features of ERP systems. The so called know-how is the most common thing that many of the small businesses out there lack. And this could be the difference between the self-made, tumultuous flowing company and the average company. At some point of the feel cycle of an enterprise, the need of such a system occasions inevitable. The earlier managers understand this, the better.As the company grows, its control becomes more and more difficult task. An unified solution, like ERP software, could be unfeignedly helpful in this situation. Every small company, that wants to grow big just needs to use an ERP sy stem. Some big corporations even would not do business with you, if you hadnt such a software implemented and working in your business. Such a solution is a proof for higher quality and that you are running your enterprise well and effectively.There are many many benefits coming from these systems, after well talk about them more. ERP solutions are from the group of ruffled systems, which means that they are built to integrate any part of your business. Initially the manager in a small company can coordinate the different departments relatively easy, but when the company starts to grow, the comparable happens with the size and number of departments. The coordination between them becomes really hard and expensive. At some point of time a crisis of control is inevitable. ERP systems can bemanagers best friend then, because this is one of their main persona to integrate your business.Advantages & Disadvantages of ERP (Enterprise resource Planning) SystemsIn order to understand com puter networks better, it would be helpful to have an overview of the applications running on the network. ERP or Enterprise Resource Planning is an important enterprise application that integrates all the individual department functions into a single software application. ERP Systems make it easier to track the workflow crossways different departments. They reduce the operational costs involved in manually tracking and (perhaps) duplicating data using individual & disparate systems. In this article, let us have a look at the advantages and dis-advantages of implementing ERP (Enterprise Resource Management) software Systems.Advantages of ERP (Enterprise Resource Planning)1. Complete visibility into all the important processes, across assorted departments of an organization (especially for senior management personnel). 2. Automatic and coherent workflow from one department/function to another, to ensure a smooth transition and quicker completion of processes. This also ensures th at all the inter-departmental activities are properly tracked and no(prenominal) of them is missed out. 3. A unified and single reporting system to analyze the statistics/status etc. in real-time, across all functions/departments. 4. Since same (ERP) software is now used across all departments, individual departments having to buy and maintain their own software systems is no longer necessary. 5. Certain ERP vendors can extend their ERP systems to provide Business Intelligence functionalities, that can give overall insights on business processes and identify potential areas of problems/improvements. 6. Advanced e-commerce integration is possible with ERP systems most of them can handle web-based order tracking/ processing.7. There are various modules in an ERP system like Finance/Accounts, Human Resource Management, Manufacturing, Marketing/Sales, Supply Chain/Warehouse Management, CRM, Project Management, etc. 8. Since ERP is a modular software system, its possible to implement either a few modules (or) many modules based on the requirements of an organization. Ifmore modules implemented, the integration between various departments may be better. 9. Since a Database system is implemented on the backend to store all the information required by the ERP system, it enables centralized storage/back-up of all enterprise data.10. ERP systems are more secure as centralized guarantor policies can be applied to them. All the transactions happening via the ERP systems can be tracked. 11. ERP systems provide better company-wide visibility and hence enable better/faster collaboration across all the departments. 12. It is possible to integrate other systems (like suspend- work out reader, for example) to the ERP system through an API (Application Programing Interface). 13. ERP systems make it easier for order tracking, inventory tracking, revenue tracking, sales forecasting and related activities. Disadvantages of ERP (Enterprise Resource Planning)1. The cost of ERP S oftware, planning, customization, configuration, testing, implementation, etc. is too high. 2. ERP deployments are highly time-consuming projects may take 1-3 years (or more) to get completed and fully functional. 3. Too little customization may not integrate the ERP system with the business process & too much customization may slack off down the project and make it difficult to upgrade. 4. The cost savings/ retribution may not be realized immediately after the ERP implementation & it is quite difficult to measure the same. 5. The participation of users is very important for successful implementation of ERP projects hence, exhaustive user training and simple user port might be critical. But ERP systems are generally difficult to learn (and use).6. There maybe additional indirect costs due to ERP implementation like new IT infrastructure, upgrading the WAN links, etc. 7. Migration of existing data to the new ERP systems is difficult (or impossible) to achieve. Integrating ERP sys tems with other stand alone software systems is evenly difficult (if possible). These activities may consume a lot of time, money & resources, if attempted. 8. ERP implementations are difficult to achieve in decentralized organizations with disparate business processes and systems. 9. erstwhile an ERP systems is implemented it becomes a single vendor lock-in for further upgrades, customizations etc. Companies are at the discretion of a single vendor and may not be able to negotiate effectively for their services. 10. Evaluation prior to implementation of ERP system is critical. If this stepis not done properly and experienced technical/business resources are not available while evaluating, ERP implementations can (and have) become a failureADVANTAGES AND DISADVANTAGES OF BARCODINGBar work outs consist of blocks and spaces that vary in width. The bars and spaces on a bar code correspond to numbers and letters that represent descriptive data. Scanners scan the bar code to find the tally description of the item, including the make and model of an item and its price. Many stores and shops commonly use bar code technology for stock inventory. Its also used to scan when a customer wants to purchase it. There are advantages and disadvantages regarding the use of bar code technology.the Disadvantages of Barcodesdisadvantages of Bar CodesTimeIn the flaunt of an eye, scanning a bar code instantly displays the product name, display case of product and price. Bar codes also have a 12-digit product number that when entered also produces the same information. However, if a bankrupt has a long line of impatient customers, entering the product details of each item is time-consuming, especially in grocery stores where each customer usually purchases multiple items. Although bar codes are a huge advantage when it comes to time, it can also be a disadvantage if the bar code on the product doesnt correspond to the right product, or the bar code scanner isnt workingInvento ryInventory is a huge component of any goods and services business. Keeping track of inventory can be a tedious, time-consuming and difficult task to do without a bar code scanner. With a bar code scanner, shop owners simply scan the bar code on the items and keep track of the stores inventory that way. When an individual purchases an item, the scanner transmits this information to the computer and its calculated on the stock inventory via computer technology. The major disadvantage here is if the cashier sees a number of items that look or seem the same and scans one item multiple times to savetime. Each item and typecast of item has a unique bar code and must be scanned separately. As a result, this could affect inventory.LabelsLabels make it easy for bar code scanners and computers to recognize the product item and vendor name. But when a commemorate is damaged or non-existent, it poses problems. Damaged labels make it difficult for the cashier to scan. Even the 12-digit number on the label may be damaged to the point where it is not legible. When this occurs, the checkout process is significantly delayed while the same product is sought out and brought to the cashier for scanning. In addition, some products, such as fruits and vegetables at grocery stores, dont have labels, which potentially cause delay. However, cashiers are usually trained to remember the 12-digit number corresponding to items without labels.CostsWhile bar code technology drastically reduces the time and energy spent on inventory and checkout procedures, it is costly. Businesses that want to implement bar code equipment and technology have to withstand the growing straining of doing so. This includes training employees, installing the equipment, expensive printers and the time spent entering codes for labels. However, disdain the disadvantages with start-up, the bar code technology benefits businesses in the long run. CONCLUSION ON THE ABOVE INVENTORY MANAGEMENT TOOLSOne should start by dictum that inventory management is the active control program that facilitates the management of sales, purchases and disbursements. The inventory management is all about special software that would reduce the costs and human efforts required to create invoices, purchase orders, various receiving lists, or payment receipts. The inventory management attempts to coordinate all the efforts in the warehouse, retail and other product lines in order to develop better controls of the processes that go indoors the organization. Speaking about a particular software, I would like to note that one of the many is available at http//www.advanceware.net/modules.asp. The software is said to provide allthe needed inventory management tools in just one package. The website provides a demo version of the software where one is able to search the shipping module.The software allows the company to print serial numbers on an invoice, set a default tax rate, generate several types of reports, rece ive and process various customer/vendor returns, and place/process customer orders in various currencies. As for the inventory management in the piece of work I would like to note that because I work in the hotel industry, the inventory management is different here than in other industries. The inventory that hotel manages is the direction space available for rental.One should understand that because hotel industry sells services the indelicate inventory management might mean that the hotel will not fill up all the rooms. Thus, the inventory management for the hotel industry should focus on the timeliness with respect to room occupation and marketing. The inventory management should also account for the food, towels, bed sheets, and other items required for the daily hotel operations. The inventory management should assure that the hotel rooms are filled right after they are freed, otherwise, the hotel would lose out since unlike tangible inventory, the service hotel industry offe rs cannot be sReferencesHarris, Ford W. (1990) Reprint from 1913. How Many Parts to Make at formerly. Operations Research (INFORMS) 38 (6) 947950. doi10.1287/opre.38.6.947. JSTOR 170962. Retrieved Nov 21, 2012. edit Hax, AC and Candea, D. (1984), mathematical product and Operations Management, Prentice-Hall, Englewood Cliffs, NJ, p. 135 Grubbstrm, Robert W. (1995). Modelling production opportunities an historical overview. International ledger of Production Economics 41 114. doi10.1016/0925-5273(95)00109-3. Nahmias, Steven (2005). Production and operations analysis. McGraw Hill Higher Education. edit Altintas, N. Erhun, F. Tayur, S. (2008). Quantity Discounts Under Demand incertitude. Management Science 54 (4) 777792. doi10.1287/mnsc.1070.0829. edit Andrew Caplin and butt Leahy, Economic