Zaheer, Kashif Bin, Mohd Ismail Bin Abd Aziz, Amber Nehan Kashif, and Syed Muhammad Murshid Raza. “Two Stage Portfolio Selection and Optimization Model With the Hybrid Particle Swarm Optimization”. MATEMATIKA: Malaysian Journal of Industrial and Applied Mathematics 34, no. 1 (May 28, 2018): 125–141. Accessed September 28, 2021. https://matematika.utm.my/index.php/matematika/article/view/1001.