@article{MASLO_1971_21_4_a6,
     author = {Pond\v{e}l{\'\i}\v{c}ek, Bed\v{r}ich},
     title = {A {Note} on {Classes} of {Regularity} in {Semigroups}},
     journal = {Mathematica slovaca},
     pages = {312--317},
     year = {1971},
     volume = {21},
     number = {4},
     mrnumber = {0301122},
     zbl = {0235.20057},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/MASLO_1971_21_4_a6/}
}