sack, K., & linsel, h. (1966). planning of technical progress in socialist countries: Planning of research and development. the institute of national planning.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)sack, K., و hermann linsel. Planning of Technical Progress in Socialist Countries: Planning of Research and Development. cairo: the institute of national planning, 1966.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)sack, K., و hermann linsel. Planning of Technical Progress in Socialist Countries: Planning of Research and Development. the institute of national planning, 1966.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.