Ajuna, L. H., H. Dukalang, and M. Ardi. “Building an Optimal Portfolio of Sharia-Compliant Stocks Using the Markowitz Model: A Study of Listed JII Companies”. Jurnal Ekonomi & Keuangan Islam, vol. 11, no. 2, Sept. 2025, pp. 314-30, doi:10.20885/JEKI.vol11.iss2.art10.