Guan, Jinying, Jiawei He, Sisi Peng, and Tiantian Xue. “Comparisons to Investment Portfolios under Markowitz Model and Index Model Based on US’s Stock Market”. BCP Business & Management 26 (September 19, 2022): 905–915. Accessed May 1, 2026. https://bcpublication.org/index.php/BM/article/view/2053.