@article{10_21136_CPM_1953_117094,
     author = {Pt\'ak, Vlastimil},
     title = {Vno\v{r}itelnost semigrup},
     journal = {\v{C}asopis pro p\v{e}stov\'an{\'\i} matematiky},
     pages = {259--261},
     publisher = {mathdoc},
     volume = {078},
     number = {3},
     year = {1953},
     doi = {10.21136/CPM.1953.117094},
     mrnumber = {0079595},
     zbl = {0053.34802},
     language = {cs},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CPM.1953.117094/}
}