@article{BUMI_1966_3_21_2_a3,
     author = {Dawson, David F.},
     title = {On subgroups of semigroups.},
     journal = {Bollettino della Unione matematica italiana},
     pages = {144--146},
     publisher = {mathdoc},
     volume = {Ser. 3, 21},
     number = {2},
     year = {1966},
     zbl = {0143.03003},
     mrnumber = {202872},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/BUMI_1966_3_21_2_a3/}
}