Παραπομπή APA

Kohler, H. (1972). What economics is all about. The dryden press.

Παραπομπή Chicago Style

Kohler, Heinz. What Economics Is All About. Illinois: The dryden press, 1972.

Παραπομπή MLA

Kohler, Heinz. What Economics Is All About. The dryden press, 1972.