@article{SF_1972__4_133917,
     author = {F.R. McMorris},
     title = {The maximal quotient semigroup.},
     journal = {Semigroup forum},
     pages = {360--364},
     publisher = {mathdoc},
     volume = {4},
     year = {1972},
     zbl = {0263.20041},
     url = {http://geodesic.mathdoc.fr/item/SF_1972__4_133917/}
}