RAFIANA A. S., A. B.; MAULANA, M. I.; ANWAR; BURHANUDDIN; NURMAN. OPTIMAL PORTFOLIO FORMATION ANALYSIS USING THE SINGLE INDEX MODEL DURING THE COVID-19 PANDEMIC: A Study on The LQ 45 Index on the Indonesian Stock Exchange (IDX). JOURNAL OF HUMANITIES, SOCIAL SCIENCES AND BUSINESS, [S. l.], v. 2, n. 3, p. 468–481, 2023. DOI: 10.55047/jhssb.v2i3.625. Disponível em: https://ojs.transpublika.com/index.php/JHSSB/article/view/625. Acesso em: 7 mar. 2026.