Sirait, H., W. N. . Hanifah, D. . Anggraeni, and S. A. . Christanti. “Analysis of Optimal Stock Portfolio Formation Using the Single Index Model As the Basis for Investment Decisions”. Eduvest - Journal of Universal Studies, vol. 4, no. 12, Dec. 2024, pp. 11560-78, doi:10.59188/eduvest.v4i12.1805.