@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/