Ferguson, Kitty [Den muslimske gullalderen fra Google Books Pythagoras: His Lives and the Legacy of a Rational Universe] Walker Publishing Company, New York, 2008, (page number not available – occurs toward end of Chapter 13, "The Wrap-up of Antiquity"). "It was in the Near and Middle East and North Africa that the old traditions of teaching and learning continued, and where Christian scholars were carefully preserving ancient texts and knowledge of the ancient Greek language."
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Monika Gronke: Geschichte Irans: Von der Islamisierung bis zur Gegenwart. C. H. Beck 2003, ISBN 3406480217, s. 30-31
