GUIDORlZZI, HAMILTON LUIZ. “THE FAMILY OF FUNCTIONS $S_{\alpha, k}$ AND THE LIENARD EQUATION”. Tamkang Journal of Mathematics 27, no. 1 (March 1, 1996): 37–54. Accessed April 12, 2025. https://journals.math.tku.edu.tw/index.php/TKJM/article/view/4368.