Gaya APA

Bontadelli, E, P, D, W, G, S, J, A. (1989). Engineering economy (Eighth Edition). : Macmillan Publishing Company.

Gaya MLA

Bontadelli, E., Paul, DeGarmo,, William, G, Sullivan,, James, A.. "Engineering economy". Eighth Edition : Macmillan Publishing Company, 1989. Text.