@article{CMUC_1963__4_1_a0,
     author = {Kr\'al, Josef},
     title = {On cyclic and radial variations of a plane path {(Preliminary} communication)},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {3--9},
     publisher = {mathdoc},
     volume = {04},
     number = {1},
     year = {1963},
     mrnumber = {0159930},
     zbl = {0147.09804},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1963__4_1_a0/}
}