Mahrat, I. M., and F. A. F. Abdul Hamid. “The Umayyad Caliphate in Andalusia: Its Diplomatic Relations With the German Empire (316-366 / 929-976)”. Al-Muqaddimah: Online Journal of Islamic History and Civilization, vol. 5, no. 1, May 2017, pp. 86-92, https://sare.um.edu.my/index.php/MUQADDIMAH/article/view/11125.