Dina Patrisia, Megawati, Dan Yolanda Erivo. 2020. “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 29 (04), 3334 -. http://sersc.org/journals/index.php/IJAST/article/view/24212.