@article{GDZPPN002304287,
title = {Periodic Solutions of Nonlinear Wave-Equations with a Dissipative Term.},
journal = {Mathematische Annalen},
volume = {189},
year = {1970},
pages = {313-322},
zbl = {0198.43704},
url = {http://dml.mathdoc.fr/item/GDZPPN002304287}
}
WAHL, W. von. Periodic Solutions of Nonlinear Wave-Equations with a Dissipative Term.. Mathematische Annalen, Tome 189 (1970) pp. 313-322. http://gdmltest.u-ga.fr/item/GDZPPN002304287/