Holland, Tom; In the Shadow of the Sword; Little, Brown; 2012; pp. 303: ‘Otherwise, in all the vast corpus of ancient literature, there is not a single reference to Mecca – not one’ The New Encyclopædia Britannica: Micropædia Volume 8: Encyclopædia Britannica, Inc. 1995. pp. 473.
Truy cập ngày 1 tháng 1 năm 2008.  ^ Holland, Tom; In the Shadow of the Sword; Little, Brown; 2012; Page 303: ‘Otherwise, in all the vast corpus of ancient literature, there is not a single reference to Mecca – not one’ ^ The New Encyclopædia Britannica: Micropædia Volume 8.