gives a mechanism for initiating and controlling the flow of materials through a supply chain
purchasing
responsible for acquiring all materials needed by an organization
procurement
interested in finished products
retail
concern with producing and distributing finished goods down stream to a wholesaler and retailers
manufacturer
family, friends, neighbor and acquaintance and etc
personals sources
advertising, salespeople, dealers, packing, display and etc
commercial source
mass media, consumer rating organizations, etc. they also become confidential to provide information
public sources