Al Taher، A. A. A.، و Spaeth، H. J. W. (1987). IRRIGATION EFFICIENCY AND PRODUCTION ENERGY EFFICIENCY OF TRADITIONAL AND MODERN FARMS IN THE AL-HASSA OASIS, SAUDI ARABIA (رسالة دكتوراه غير منشورة). Oklahoma University، نورمان. مسترجع من http://search.mandumah.com/Record/617655
Al Taher، Abd Alla A.، و Hans Joachim W. Spaeth. "IRRIGATION EFFICIENCY AND PRODUCTION ENERGY EFFICIENCY OF TRADITIONAL AND MODERN FARMS IN THE AL-HASSA OASIS, SAUDI ARABIA" رسالة دكتوراه. Oklahoma University، نورمان، 1987. مسترجع من http://search.mandumah.com/Record/617655