Muhammad M. Hakim, Nurhayati, and Joko Setiawan. “Designing Optimal Green Investment Portfolio Using Markowirtz Model”. Jurnal Bisnis, Ekonomi, Manajemen, dan Kewirausahaan 4, no. 2 (December 31, 2024): 103–116. Accessed September 21, 2025. https://www.abnus.org/jbemk/article/view/184.