@article{SF_1977__14_186361,
     author = {C.C. Edwards},
     title = {The greatest idempotent separating congruence on an ....-unipotent semigroup.},
     journal = {Semigroup forum},
     pages = {127--136},
     publisher = {mathdoc},
     volume = {14},
     year = {1977},
     zbl = {0368.20045},
     url = {http://geodesic.mathdoc.fr/item/SF_1977__14_186361/}
}