E. V. Putri and W. Hariyanto, “Comparative Analysis of Expected Return and Portfolio Risk in Formation of Optimal Portfolios Using the Capital Asset Pricing Model (Capm) and Single Index Methods: Analisis Perbandingan Expected Return dan Risiko Portofolio dalam Pembentukan Portofolio Optimal Menggunakan Metode Capital Asset Pricing Model (Capm) dan Indeks Tunggal”, acopen, vol. 5, p. 10.21070/acopen.5.2021.2371, Dec. 2021.