@article{10_1017_S0017089500001051,
     author = {Hotzel, E.},
     title = {On semigroups whose nontrlvial left congruence classes are left ideals{\textdagger}},
     journal = {Glasgow mathematical journal},
     pages = {1--5},
     year = {1971},
     volume = {12},
     number = {1},
     doi = {10.1017/S0017089500001051},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089500001051/}
}