@article{CMUC_1971__12_1_a2,
     author = {Ne\v{s}et\v{r}il, Jaroslav},
     title = {Every group is a maximal subgroup of the semigroup of relations},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {19--21},
     publisher = {mathdoc},
     volume = {12},
     number = {1},
     year = {1971},
     mrnumber = {0283123},
     zbl = {0221.20093},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1971__12_1_a2/}
}