@article{10_1017_S0017089500007126,
     author = {Byleen, Karl},
     title = {Embedding any countable semigroup without idempotents in a 2-generated simple semigroup without idempotents},
     journal = {Glasgow mathematical journal},
     pages = {121--128},
     year = {1988},
     volume = {30},
     number = {2},
     doi = {10.1017/S0017089500007126},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089500007126/}
}