Boayo, Suleiman M. H. “’Islam’ and the Decline of Civilization: Deconstruction of Historiosophy of Oswald Spengler and Henri Pierenne”. Al-Shajarah: Journal of the International Institute of Islamic Thought and Civilization (ISTAC) 12, no. 1 (November 2, 2014). Accessed May 6, 2024. https://journals.iium.edu.my/shajarah/index.php/shaj/article/view/63.