Bazmee Ansari, A.S. (1991). "Daybul". The Encyclopedia of Islam, New Edition, Volume II: C–G. Leiden and New York: BRILL. pp. 188–189. ISBN90-04-07026-5.
Al-Tabari, Abu Ja'far Muhammad ibn Jarir (1985–2007). Ehsan Yar-Shater (ed.). The History of Al-Ṭabarī. Vol. 40 vols. Albany, NY: State University of New York Press.