C. E. Bosworth, «AZERBAIJAN iv. Islamic History to 1941» in Encyclopaedia Iranica. [1](accessed novembre 2010): "In ca. 279/892 the caliph Moʿtażed appointed one of his generals, Moḥammad b. Abi'l-Sāj, an Iranian from Central Asia, as governor of Azerbaijan and Armenia, and the family of the Sajids "
