R. Joy Salomi, S. Vinolyn Sylvia, D. Gowthaman. “NONLINEAR ROLL MOTION OF SHIPS USING AKBARI-GANJI METHOD”. International Journal of Advanced Science and Technology, Vol. 29, no. 6s, Apr. 2020, pp. 311 -7, http://sersc.org/journals/index.php/IJAST/article/view/8765.