Dina Patrisia, Megawati, Dan Yolanda Erivo. “Analysis of the Optimal Portfolio Formation of a Single Index Model for Making Investment Decisions on the Indonesia Stock Exchange on LQ-45 Stock”. International Journal of Advanced Science and Technology, Vol. 29, no. 04, June 2020, pp. 3334 -, http://sersc.org/journals/index.php/IJAST/article/view/24212.