@article{GDZPPN002205955,
title = {On the blowing up of solutions to nonlinear wave equations in two space dimensions.},
journal = {Journal f\"ur die reine und angewandte Mathematik},
volume = {390},
year = {1988},
pages = {55-64},
zbl = {0649.35062},
url = {http://dml.mathdoc.fr/item/GDZPPN002205955}
}
Rammaha, M.A. On the blowing up of solutions to nonlinear wave equations in two space dimensions.. Journal für die reine und angewandte Mathematik, Tome 390 (1988) pp. 55-64. http://gdmltest.u-ga.fr/item/GDZPPN002205955/