1. “Al-Ma’mūn,” M. Rekaya, The Encyclopaedia of Islam, Vol VI, 331.
2. Astronomy and Astrology in the Medieval Islamic World
www.metmuseum.org/toah/hd/…/hd_astr.ht
3. Astronomy – Institute of Arabic and Islamic Studies
www.islamic-study.org/astronomy.htm
4. Baghdad: Libraries and House of Wisdom
http://www.whyislam.org/muslim-world/baghdad-libraries-house-of-wisdom/
5. Celestial Navigation
http://ecampus.matc.edu/mihalj/astronomy/test1/celestial_navigation.html