@article{10_21136_CMJ_1960_100403,
     author = {Schwarz, \v{S}tefan},
     title = {A theorem on normal semigroups},
     journal = {Czechoslovak Mathematical Journal},
     pages = {197--200},
     publisher = {mathdoc},
     volume = {10},
     number = {2},
     year = {1960},
     doi = {10.21136/CMJ.1960.100403},
     mrnumber = {0116075},
     zbl = {0098.01704},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1960.100403/}
}