@article{10_21136_AM_1974_103537,
     author = {V{\'\i}tek, V\'aclav},
     title = {Periodic solutions of a weakly nonlinear hyperbolic equation in $E_2$ and $E_3$},
     journal = {Applications of Mathematics},
     pages = {232--245},
     publisher = {mathdoc},
     volume = {19},
     number = {4},
     year = {1974},
     doi = {10.21136/AM.1974.103537},
     mrnumber = {0402292},
     zbl = {0311.35004},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/AM.1974.103537/}
}