@article{10_4153_CMB_1972_056_8,
     author = {McMorris, F. R.},
     title = {The {Singular} {Congruence} and the {Maximal} {Quotient} {Semigroup}},
     journal = {Canadian mathematical bulletin},
     pages = {301--303},
     year = {1972},
     volume = {15},
     number = {2},
     doi = {10.4153/CMB-1972-056-8},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-1972-056-8/}
}