Dyfyniad APA
Heinritz, S. F., Farrell, P. V., & Smith, C. L. (1986). Purchasing: Principles and applications (7th ed.). Prentice-Hall.
Dyfyniad Arddull Chicago
Heinritz, Stuart F., Paul V. Farrell, and Clifton L. Smith. Purchasing: Principles and Applications. 7th ed. Englwood Cliffs, N.J.: Prentice-Hall, 1986.
Dyfyniad MLA
Heinritz, Stuart F., et al. Purchasing: Principles and Applications. 7th ed. Prentice-Hall, 1986.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.