Khan, M.M.A., H. Abbas, and N.K. Gupta. “Analysis of Axisymmetric Crushing of Frusta”. Defence Science Journal 53, no. 1 (January 1, 2003): 41-50. Accessed July 10, 2020. https://publications.drdo.gov.in/ojs/index.php/dsj/article/view/2127.