Ying Wang, and Ziheng Zhang. “Homoclinic Solutions for Some Nonperiodic Fourth Order Differential Equations With Sublinear Nonlinearities”. Journal of Advances in Applied & Computational Mathematics 4, no. 1 (December 19, 2017): 15–22. Accessed July 13, 2025. https://ijaet-journal.org/index.php/jaacm/article/view/837.