tinbergen, j. (1964). development planning: The sector phase with different gestation periods. the institute of national planning.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)tinbergen, j. Development Planning: The Sector Phase with Different Gestation Periods. cairo: the institute of national planning, 1964.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)tinbergen, j. Development Planning: The Sector Phase with Different Gestation Periods. the institute of national planning, 1964.