Piotrowski, R. (1978). Cartels and trusts: Their origin and historical development from the economic and legal aspects. Porcupine Press.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Piotrowski, Roman. Cartels and Trusts: Their Origin and Historical Development from the Economic and Legal Aspects. Philadelphia: Porcupine Press, 1978.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)Piotrowski, Roman. Cartels and Trusts: Their Origin and Historical Development from the Economic and Legal Aspects. Porcupine Press, 1978.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.