Gaya APA

Ekelund, R, B., Tollison, R, D. (1988). Economics Ed. 2 (Ke-2). Amerika: Scott, Foresman and Company.

Gaya MLA

Ekelund, Robert, B.., Tollison, Robert, D.. "Economics Ed. 2". Ke-2 Amerika: Scott, Foresman and Company, 1988. Text.