@article{CMUC_1980__21_2_a9,
     author = {Lee, Sin Min},
     title = {On a simple one-element extension of left zero semigroups},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {313--318},
     publisher = {mathdoc},
     volume = {21},
     number = {2},
     year = {1980},
     mrnumber = {580686},
     zbl = {0437.08005},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1980__21_2_a9/}
}