Shavana, Shavana Aditya Yolanda, Syaparuddin Syaparuddin, Syamsurijal Tan Syamsurijal Tan, and Syaparuddin Syaparuddin. “A Study of Income Inequality on Sumatra Island”. The Asian Journal of Professional & Business Studies 5, no. 1 (June 29, 2024): 263–278. Accessed May 31, 2026. https://journal.uptm.edu.my/index.php/ajpbs/article/view/318.