@article{MOMA_1964__68_177253,
     author = {Z. Hedrlin and A. Pultr},
     title = {Relations {(Graphs)} with {Given} {Finitely} {Generated} {Semigroups.}},
     journal = {Monatshefte f\"ur Mathematik},
     pages = {213--217},
     publisher = {mathdoc},
     volume = {68},
     year = {1964},
     zbl = {0126.26602},
     url = {http://geodesic.mathdoc.fr/item/MOMA_1964__68_177253/}
}