Heidari Tavani, Mohammad Reza, and Abdollah Nazari. “Multiple Periodic Solutions for a Class of P-Hamiltonian Systems”. The Journal of the Indian Mathematical Society 89, no. 3-4 (August 23, 2022): 419–429. Accessed May 9, 2024. http://informaticsjournals.com/index.php/jims/article/view/24941.