Rahayu, Wiji, and Wiwit Hariyanto. “Analysis of Portfolio Expected Returns As a Material Consideration for Investors in Choosing Investments in the Pandemic Period (Formation of Optimal Portfolios Using the Black Litterman Model on Hang Seng Stocks for the 2017-2019 Period)”. Academia Open 50 (December 31, 2021): 10.21070/acopen.5.2021.2149. Accessed April 24, 2024. https://acopen.umsida.ac.id/index.php/acopen/article/view/2149.