Di, Huafei, and Yadong Shang. “Existence, Nonexistence and Decay Estimate of Global Solutions for a Viscoelastic Wave Equation With Nonlinear Boundary Damping and Internal Source Terms”. European Journal of Pure and Applied Mathematics 10, no. 4 (July 11, 2017): 668–701. Accessed August 13, 2022. https://ejpam.com/index.php/ejpam/article/view/3003.