1. Manufacturing Skill Standards Council (MSSC). (2015). MSSC National Skill Standards for Logistics. Critical Work Function: Receiving, Key Activity 2. "Verify materials and quantities received against the purchase order and packing slip."
2. Richards, G. (2017). Warehouse Management: A Complete Guide to Improving Efficiency and Minimizing Costs (3rd ed.). Kogan Page. Chapter 5, "Receiving and put-away," p. 98. The text describes the standard procedure: "The first check is normally against a copy of the purchase order... The checker will then proceed to check the goods against the delivery note/packing list."
3. Bowersox, D. J., Closs, D. J., & Cooper, M. B. (2020). Supply Chain Logistics Management (5th ed.). McGraw-Hill. Chapter 9, "Warehousing," Section: Receiving. This section details the receiving process, which includes "checking the shipment against the purchase order."