HALIM, H., YUSOFF, K., AHMAD, S., ABDUL KHIR, M. F., ABDULLAH, A. H., BASIR, A., & SYED ABU BAKAR, S. K. (2018). SUMBER-SUMBER KAJIAN TERHADAP KEWUJUDAN NEGARA ISLAM VOLGA BULGARIA 922 MASEHI. Human Sustainability Procedia. https://publisher.uthm.edu.my/periodicals/index.php/hsp/article/view/1186