Παραπομπή APA

Cassles, J. W. W. (1960). How to sell successfully by direct mail (IV.).

Παραπομπή Chicago Style

Cassles, J W W. How to Sell Successfully by Direct Mail. IV. :, 1960.

Παραπομπή MLA

Cassles, J W W. How to Sell Successfully by Direct Mail. IV. 1960.