Gusliana, Shindi Adha, and Yasir Salih. “Mean-Variance Investment Portfolio Optimization Model Without Risk-Free Assets in Jii70 Share”. Operations Research: International Conference Series 3, no. 3 (September 4, 2022): 101–106. Accessed January 14, 2026. https://www.iorajournal.org/index.php/Orics/article/view/185.