Productivity Services International. (1971). Fortune-making in your spare time: Seventy propositions. Productivity services international.
শিকাগো স্টাইলে সাইটেশনProductivity Services International. Fortune-making in Your Spare Time: Seventy Propositions. Bombay: Productivity services international, 1971.
এমএলএ সাইটেশনProductivity Services International. Fortune-making in Your Spare Time: Seventy Propositions. Productivity services international, 1971.
সতর্কবাণী: সাইটেশন সবসময় 100% নির্ভুল হতে পারে না.