Haji Hamzah, Norhayati. “The Government of Khurasan Under the Early Abbasid Caliphs (A.H. 136-170/A.D. 753-785)”. Jurnal Usuluddin 19 (June 30, 2004): 139–158. Accessed April 30, 2025. http://jice.um.edu.my/index.php/JUD/article/view/4148.