@article{MASLO_1961_11_1_a0,
     author = {Wiegold, James},
     title = {Semigroup {Coverings} of {Groups}},
     journal = {Mathematica slovaca},
     pages = {3--13},
     year = {1961},
     volume = {11},
     number = {1},
     mrnumber = {0158946},
     zbl = {0104.01902},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/MASLO_1961_11_1_a0/}
}