@article{CMUC_1977__18_2_a15,
     author = {Trnkov\'a, V\v{e}ra},
     title = {Productive representations of semigroups by pairs of structures},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {383--391},
     publisher = {mathdoc},
     volume = {18},
     number = {2},
     year = {1977},
     mrnumber = {0444732},
     zbl = {0359.54030},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1977__18_2_a15/}
}