Ariantara, Made Arvin, Ni Putu Riza Oktayanti, I Made Astawa, and Laode Rahim. “Application of The Single Index Model to Determine Optimal Portfolio Composition in IDXG30 Stocks (2021-2024)”. Journal of Economics and Management Scienties 7, no. 4 (July 21, 2025): 564–570. Accessed January 20, 2026. http://jems.ink/index.php/JEMS/article/view/190.