@article{CMUC_1963_4_3_a8,
     author = {Hedrl{\'\i}n, Zden\v{e}k},
     title = {On a number of commuting transformations},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {132--136},
     year = {1963},
     volume = {4},
     number = {3},
     mrnumber = {0168476},
     zbl = {0134.01703},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1963_4_3_a8/}
}