Nanta Kumar, Umeesh, and Yaan Yee Choy. “The Solitary Waves in Fluid Filled Elastic Tube With Variable Radius”. Enhanced Knowledge in Sciences and Technology, vol. 1, no. 2, July 2021, pp. 218-24, https://publisher.uthm.edu.my/periodicals/index.php/ekst/article/view/2768.