@article{10_21136_AM_1974_103527,
     author = {Zelinka, Bohdan},
     title = {Polar graphs and railway traffic},
     journal = {Applications of Mathematics},
     pages = {169--176},
     publisher = {mathdoc},
     volume = {19},
     number = {3},
     year = {1974},
     doi = {10.21136/AM.1974.103527},
     mrnumber = {0347346},
     zbl = {0283.05116},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/AM.1974.103527/}
}