ZHANG, Xindong, and Juan LIU. “An Analytic Study on Time-Fractional Fisher Equation Using Homotopy Perturbation Method”. Walailak Journal of Science and Technology (WJST) 11, no. 11 (January 20, 2014): 975–985. Accessed April 28, 2024. https://wjst.wu.ac.th/index.php/wjst/article/view/844.