Gaya APA

F.Heathfield, D., Wibe, S. (1987). An Inttroduction to cost and production funtions/David F.Heathfield (^a2 ^bjilid 1). Hong kong: Macmillan Eduation.

Gaya MLA

F.Heathfield, David., Wibe, Soren. "An Inttroduction to cost and production funtions/David F.Heathfield". ^a2 ^bjilid 1 Hong kong: Macmillan Eduation, 1987. Text.