Voir la notice de l'article provenant de la source Math-Net.Ru
@article{MZM_2004_76_3_a11, author = {I. A. Rudakov}, title = {Periodic {Solutions} of a {Nonlinear} {Wave} {Equation} with {Nonconstant} {Coefficients}}, journal = {Matemati\v{c}eskie zametki}, pages = {427--438}, publisher = {mathdoc}, volume = {76}, number = {3}, year = {2004}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/MZM_2004_76_3_a11/} }
I. A. Rudakov. Periodic Solutions of a Nonlinear Wave Equation with Nonconstant Coefficients. Matematičeskie zametki, Tome 76 (2004) no. 3, pp. 427-438. http://geodesic.mathdoc.fr/item/MZM_2004_76_3_a11/