Gaya APA

Walstad, W, B., Bingham, R, C. (2002). Study guide to accompany economics : Principle, problems, and policies (15). New York: McGraw-Hill.

Gaya MLA

Walstad, William, B.., Bingham, Robert, C.. "Study guide to accompany economics : Principle, problems, and policies". 15 New York: McGraw-Hill, 2002. Text.