Norma, Norma, Arni Surwanti, and Alni Rahmawati. “The Analysis of Optimal Portfolio on Investment Decision Using Single Index Model on LQ45 Stocks (Listed on Indonesia Stock Exchange for The Period 2022-2024)”. Journal of Economics and Management Scienties 7, no. 4 (July 31, 2025): 670–677. Accessed October 23, 2025. https://jems.ink/index.php/JEMS/article/view/204.