The following publications are possibly variants of this publication:
- Eight Limit cycles around a Center in quadratic Hamiltonian System with Third-Order perturbationPei Yu, Maoan Han. IJBC, 23(1), 2013. [doi]
- Nine limit cycles around a singular point by perturbing a cubic Hamiltonian system with a nilpotent centerJunmin Yang, Pei Yu. amc, 298:141-152, 2017. [doi]
- Seven Limit Cycles Around a Focus Point in a Simple Three-Dimensional Quadratic Vector FieldYun Tian, Pei Yu. IJBC, 24(6), 2014. [doi]
- Limit Cycles in Two Types of Symmetric LiÉnard SystemsJ. Jiang, M. Han, P. Yu, S. Lynch. IJBC, 17(6):2169-2174, 2007. [doi]