Mat Yahya, N., A. R. Yusoff, A. Senawi, and M. O. Tokhi. “Dual Level Searching Approach for Solving Multi Objective Optimisation Problems Using Hybrid Particle Swarm Optimisation and Bats Echolocation-Inspired Algorithms”. Mekatronika: Journal of Intelligent Manufacturing and Mechatronics, vol. 1, no. 1, Jan. 2019, pp. 45-57, https://journal.ump.edu.my/mekatronika/article/view/155.