Παραπομπή APA

Producti Services International. (1971). Fortune making in your spare time: Seventy propositions. Productivity services international.

Παραπομπή Chicago Style

Producti Services International. Fortune Making in Your Spare Time: Seventy Propositions. Bombay: Productivity services international, 1971.

Παραπομπή MLA

Producti Services International. Fortune Making in Your Spare Time: Seventy Propositions. Productivity services international, 1971.