YULIANDRA, B.; HASAN, A.; REZEKI, R. Portofolio Optimal dan Pengelompokan Perusahaan Berdasarkan Pengaruh Komoditas Dunia. Jurnal Optimasi Sistem Industri, Padang, ID, v. 16, n. 1, p. 50–57, 2017. DOI: 10.25077/josi.v16.n1.p50-57.2017. Disponível em: https://josi.ft.unand.ac.id/index.php/josi/article/view/102. Acesso em: 2 may. 2024.