Devira Larasati, Ari Rohmana, Reza Mutiara, and Maria Yovita R. Pandin, “Analysis of the Single Index Model and Markowitz in Optimal Portfolio Selection in the Telecommunications Sub-Sector Listed on the Indonesia Stock Exchange for the Period 2020-2022”, Finance : International Journal of Management Finance, vol. 1, no. 2, pp. 71–85, Dec. 2023, doi: 10.62017/finance.v1i2.27.