@article{AUCMP_2011__52_2_a4,
     author = {Je\v{z}ek, Jaroslav and Kepka, Tom\'a\v{s} and N\v{e}mec, Petr},
     title = {One element extensions of commutative semigroups},
     journal = {Acta Universitatis Carolinae. Mathematica et Physica},
     pages = {33--35},
     publisher = {mathdoc},
     volume = {52},
     number = {2},
     year = {2011},
     mrnumber = {2952453},
     zbl = {1256.20056},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AUCMP_2011__52_2_a4/}
}