Dembeck, Hermann (1965). Animals and men. Natural History Press. p. 264. ISBN1-598-84347-8. //books.google.co.jp/books?id=1LS1AAAAIAAJ (参照:Dembeck, Mit Tieren leben, 1961)
Scholz 1970, p. 82, "..and the envoy of Emir Abraham, who ruled on the border of Africa in Fustât"; Scholz 1970, 801年の注4, "Harun al-Rashid, emir al Mumenin.. appointed Ibrahim ibn al'Aghlab governor of Africa about 800. Fustât, his place of residence is Abbasiya near Kairwan in southern Tunis.."
Sherman, Dennis; Salisbury, Joyce. The West in the World, Volume I: To 1715. 1 (3 ed.). New York: McGraw-Hill. p. 220. ISBN0-07-331669-5. OCLC177823124, "Chroniclers of the 'Abbasid caliphate, on the other hand, never mentioned these interactions"