Gaya APA

Ekelund, R, B., Hebert, R, F. (1997). A history of economic theory and methods (4th Ed.). New York: The McGraw-Hill Companies, Inc..

Gaya MLA

Ekelund, Robert, B.., Hebert, Robert, F.. "A history of economic theory and methods". 4th Ed. New York: The McGraw-Hill Companies, Inc., 1997. Text.