Παραπομπή APA

Cassels, J. (1960). How to sell successfully by direct mail. Business publications.

Παραπομπή Chicago Style

Cassels, J.W.W. How to Sell Successfully by Direct Mail. London: Business publications, 1960.

Παραπομπή MLA

Cassels, J.W.W. How to Sell Successfully by Direct Mail. Business publications, 1960.