Biazar, Jafar, Zeinab Ayati, and Masoome Partovi. “Homotopy Perturbation Method for Biological Species Living Together”.
International Journal of Applied Mathematical Research 2, no. 1 (November 30, 2012): 44–48. Accessed April 27, 2025.
https://sciencepubco.com/index.php/ijamr/article/view/451.