“Estimating the Number of Limit Cycles for One Step Perturbed Homogeneous Degenerate Centers”. Extracta Mathematicae 38, no. 1 (June 1, 2023): 85–104. Accessed April 18, 2024. https://revista-em.unex.es/index.php/EM/article/view/2605-5686.38.1.85.