@article{10_14712_1213_7243_2015_243,
     author = {Zubelevich, Oleg},
     title = {Periodic solutions to {Lagrangian} system},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {241--251},
     publisher = {mathdoc},
     volume = {59},
     number = {2},
     year = {2018},
     doi = {10.14712/1213-7243.2015.243},
     mrnumber = {3815689},
     zbl = {06940867},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.14712/1213-7243.2015.243/}
}