@article{JRAM_1989__398_153140,
     author = {Michael W. Smiley},
     title = {Breathers and forced oscillations of nonlinear wave equations on {R3.}},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {25--35},
     publisher = {mathdoc},
     volume = {398},
     year = {1989},
     zbl = {0666.35066},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1989__398_153140/}
}