Gaya APA

Schonberger, R., Knod, E, M. (1991). Operations management : improving costumer service (4th.ed.). Homewood: Irwin.

Gaya MLA

Schonberger, Richard., Knod, Edward, M. "Operations management : improving costumer service". 4th.ed. Homewood: Irwin, 1991. Text.