@article{SF_1971__2_133833,
     author = {D. jr. Allen},
     title = {A generalization of the {Rees} {Theorem} to a class o{\textsterling} regular semigroups.},
     journal = {Semigroup forum},
     pages = {321--331},
     publisher = {mathdoc},
     volume = {2},
     year = {1971},
     zbl = {0226.20070},
     url = {http://geodesic.mathdoc.fr/item/SF_1971__2_133833/}
}