@article{SF_1991__43_3_135112,
     author = {K. Todorov and G. Bijev},
     title = {On the representation of abstract semigroups by transformation semigroups :  {Computer} investigations.},
     journal = {Semigroup forum},
     pages = {253--256},
     publisher = {mathdoc},
     volume = {43},
     number = {3},
     year = {1991},
     zbl = {0756.20011},
     url = {http://geodesic.mathdoc.fr/item/SF_1991__43_3_135112/}
}