@article{10_21136_CPM_1957_117256,
     author = {Kurzweil, Jaroslav},
     title = {Sur l'\'equation $\ddot{x} + f(t)x = 0$},
     journal = {\v{C}asopis pro p\v{e}stov\'an{\'\i} matematiky},
     pages = {218--226},
     publisher = {mathdoc},
     volume = {082},
     number = {2},
     year = {1957},
     doi = {10.21136/CPM.1957.117256},
     mrnumber = {0094506},
     zbl = {0102.07702},
     language = {fr},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CPM.1957.117256/}
}