Ṭabarī, William Montgomery Watt, Michael V. McDonald (1987). The foundation of the community. State University of New York Press. p. 136. ISBN 978-0-88706-344-2.
Norman A. Stillman (1979). The Jews of Arab lands: a history and source book. Jewish Publication Society. p. 121. ISBN 978-0-06-123135-3. However, he was accustomed to his own religion, and this held him back.
