“Poincaré Bifurcation from an Elliptic Hamiltonian of Degree Four With Two-Saddle Cycle”. Journal of Nonlinear Modeling and Analysis 4, no. 4 (April 10, 2024): 722–735. Accessed December 6, 2025. https://global-sci.com/index.php/jnma/article/view/13667.