Zenz, G. J. (1994). Purchasing and the management of materials (7th ed.). New York: John Wiley and Sons.
Παραπομπή Chicago StyleZenz, Gary Joseph. Purchasing and the Management of Materials. 7th ed. New York: John Wiley and Sons, 1994.
Παραπομπή MLAZenz, Gary Joseph. Purchasing and the Management of Materials. 7th ed. New York: John Wiley and Sons, 1994.
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