APA استشهاد

Frye, R. W. (1973). Introduction to the marketing system. Comfield press, 1973.

استشهاد بنمط شيكاغو

Frye, Robert W. Introduction to the Marketing System. Francisco: Comfield press, 1973, 1973.

MLA استشهاد

Frye, Robert W. Introduction to the Marketing System. Comfield press, 1973, 1973.