Meliala, F. U. and 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), pp. 1884 –. doi: 10.59141/jrssem.v2i08.399.