@article{MASLO_1970__20_2_a2,
     author = {Kraj\v{n}\'akov\'a, Dorota},
     title = {On {Dual} {Semigroups}},
     journal = {Mathematica slovaca},
     pages = {87--91},
     publisher = {mathdoc},
     volume = {20},
     number = {2},
     year = {1970},
     mrnumber = {0308298},
     zbl = {0206.30403},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/MASLO_1970__20_2_a2/}
}