Irwan I, Abdy M, Salsabila NK, Ahmar AS. Analysis of Stock Portfolio Optimization in the Telecommunications Sector Using the Single Index Model. ARRUS J. Math. App. Sci. [Internet]. 2023 May 26 [cited 2026 Apr. 23];3(1):1-10. Available from: https://qemsjournal.org/index.php/mathscience/article/view/1734