Chong, Jia-Cherng, Wing-Fook Chong, and Hood-Hong Ley. “Synchronous Pendulums and Aliasing”. Journal of Science and Technology 6, no. 2 (December 22, 2014). Accessed January 26, 2020. https://publisher.uthm.edu.my/ojs/index.php/JST/article/view/941.