In 3-4 pages, explain how procurement type indicates whether a material is produced in house (via the production process), obtained externally (via the procurement process), both, or none. Give examples. (Trading goods and raw materials are obtained externally. In contrast, finished goods and semi-finished goods are produced in house.) Be sure to cite your sources.
Be sure to cover that the procurement type can be set to none for discontinued materials and set to both for materials that a company normally produces in house but does not have the resources to produce at the current time.