Gaya APA

Purvis, R, G, L, P, N, C, D, D. (1993). Economics Tenth Edition (10). New York: HarperCollins College Publishers.

Gaya MLA

Purvis, Richard, G., Lipsey., Paul, N., Courant., Douglas, D.. "Economics Tenth Edition". 10 New York: HarperCollins College Publishers, 1993. Text.