@article{10_14708_cm_v19i2_5859,
     author = {T. Jankowski},
     title = {On periodic solutions of the equation \(x'(t) = {F(t,} x(t), x'(t))\)},
     journal = {Commentationes Mathematicae},
     pages = { 249--252},
     publisher = {mathdoc},
     volume = {19},
     number = {2},
     year = {1977},
     doi = {10.14708/cm.v19i2.5859},
     language = {pl},
     url = {http://geodesic.mathdoc.fr/articles/10.14708/cm.v19i2.5859/}
}