@article{01570766,
title = {Rotationally invariant periodic solutions of semilinear wave equations.},
journal = {Abstract and Applied Analysis},
volume = {3},
year = {1998},
pages = {171-180},
doi = {10.1155/S1085337598000499},
zbl = {0973.35024},
language = {en},
url = {http://dml.mathdoc.fr/item/01570766}
}
Schechter, Martin. Rotationally invariant periodic solutions of semilinear wave equations.. Abstract and Applied Analysis, Tome 3 (1998) pp. 171-180. doi : 10.1155/S1085337598000499. http://gdmltest.u-ga.fr/item/01570766/