Gw mau tau Lihat pula dari Sumber hukum Islam

Libson, G.; Stewart, F.H. "ʿUrf." Encyclopaedia of Islam. Edited by: P. Bearman, Th. Bianquis, C.E. Bosworth, E. van Donzel and W.P. Heinrichs. Brill, 2008. Brill Online.  10 April 2008