B. Verkino, B. M. . Sinaga, and T. . Andati, “Portofolio Optimal Investasi Saham dari 6 Sektor pada Indeks LQ45 Periode 2015-2018: Optimal Portfolio Stock Investment from 8 Sectors of LQ45 During Period 2015-2018 ”, jabm, vol. 6, no. 2, p. 389, May 2020, doi: 10.17358/jabm.6.2.389.