Gaya APA

Heinritz, S, F., Farrell, P, V. (1971). Purchasing : principles and applications. (1971). : Englewood Cliffs : Prentuce-Hall, Inc.,.

Gaya MLA

Heinritz, Stuart, F.., Farrell, Paul, V.. "Purchasing : principles and applications.". 1971 : Englewood Cliffs : Prentuce-Hall, Inc.,, 1971. Text.