@article{ARM_1969__5_4_a5,
     author = {Reissig, Rolf},
     title = {Nachweis periodischer {L\"osungen} in nichtautonomen {Systemen} mit {Hilfe} des {Brouwerschen} {Fixpunktsatzes}},
     journal = {Archivum mathematicum},
     pages = {193--205},
     publisher = {mathdoc},
     volume = {05},
     number = {4},
     year = {1969},
     mrnumber = {0280809},
     zbl = {0259.34050},
     language = {ge},
     url = {http://geodesic.mathdoc.fr/item/ARM_1969__5_4_a5/}
}