Meliala, F. U., & Sukarno, S. . (2023). Optimal Investment Portfolio Analysis Using The Markowitz Model For Stock In Each Sector In The Indonesia Stock Market During Covid 19 (2020-2021). Journal Research of Social Science, Economics, and Management, 2(8), 1884 –. https://doi.org/10.59141/jrssem.v2i08.399