@article{CMH_1996__71_2_140400,
     author = {J\"urgen P\"oschel},
     title = {Quasi-periodic solutions for a nonlinear wave equation.},
     journal = {Commentarii mathematici Helvetici},
     pages = {269},
     publisher = {mathdoc},
     volume = {71},
     number = {2},
     year = {1996},
     zbl = {0866.35013},
     language = {un},
     url = {https://geodesic-test.mathdoc.fr/item/CMH_1996__71_2_140400/}
}