@article{MAN_1983__262_163706,
     author = {J.M. Coron},
     title = {Periodic {Solutions} of a {Nonlinear} {Wave} {Equation} {Without} {Assumption} of {Monotonicity.}},
     journal = {Mathematische Annalen},
     pages = {273--286},
     publisher = {mathdoc},
     volume = {262},
     year = {1983},
     zbl = {0489.35061},
     url = {http://geodesic.mathdoc.fr/item/MAN_1983__262_163706/}
}