Siagian, Pargaulan. “Article of KDBK in English 20 The Advancement of Demographics Learning Tools: The Advancement of Demographics Learning Tools”. Advances in Social Sciences Research Journal 7, no. 3 (April 4, 2020): 279–295. Accessed May 28, 2026. https://scholarpublishing.org/journals/index.php/ASSRJ/article/view/3912.