Zhang, Danni, and Ziheng Zhang. “Sign-Changing Solutions for Fourth Order Elliptic Equation With Concave-Convex Nonlinearities”. Journal of Advances in Applied & Computational Mathematics 11 (July 8, 2024): 1–16. Accessed November 7, 2024. https://avantipublishers.com/index.php/jaacm/article/view/1520.