Rachmatullah, Irsyaad, Jubaedah Nawir, and Tri Siswantini. “Analisis Portofolio Optimal Markowitz Dan Single Index Model Pada Jakarta Islamic Index”. Ekonomi dan Bisnis 8, no. 1 (July 6, 2021): 50–69. Accessed December 5, 2025. https://ejournal.upnvj.ac.id/ekobis/article/view/2682.