@article{SF_1990__41_2_135043,
     author = {K. Byleen},
     title = {Embedding any countable semigroups in a 2-generated congruence-free semigroup.},
     journal = {Semigroup forum},
     pages = {145--154},
     publisher = {mathdoc},
     volume = {41},
     number = {2},
     year = {1990},
     zbl = {0702.20045},
     url = {http://geodesic.mathdoc.fr/item/SF_1990__41_2_135043/}
}