Analysis of Formation of Optimal Portfolio Single Index Model (Study of Cigarette Sub-Sector Manufacturing Companies Period 2020-2021). West Science Journal Economic and Entrepreneurship, [S. l.], v. 1, n. 01, p. 37–41, 2023. Disponível em: https://wsj.westsciences.com/index.php/wsee/article/view/26. Acesso em: 7 dec. 2025.