@article{10_21136_CMJ_1974_101231,
     author = {Kapp, Kenneth M.},
     title = {On $n^\circ $-regular semigroups},
     journal = {Czechoslovak Mathematical Journal},
     pages = {171--175},
     publisher = {mathdoc},
     volume = {24},
     number = {2},
     year = {1974},
     doi = {10.21136/CMJ.1974.101231},
     mrnumber = {0349881},
     zbl = {0334.20028},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1974.101231/}
}