“Pembentukan Portofolio Optimal Saham Perbankan Menggunakan Single Index Model Analisis Pada Saham LQ-45 Periode 2018-2019”, J-DBS, vol. 1, no. 1, pp. 13–20, Jun. 2024, Accessed: Jul. 30, 2026. Available: https://ejournal.darunnajah.ac.id/index.php/J-DBS/article/view/196