Karachalios, Nikos, and Nikos M. Stavrakakis. 2001. “Asymptotic Behavior of Solutions of Some Nonlinearly Damped Wave Equations on $\mathbb R^N$”. Topological Methods in Nonlinear Analysis 18 (1):73-87. https://apcz.umk.pl/TMNA/article/view/TMNA.2001.024.