@article{SF_1985__31_134753,
     author = {G.M.S. Gomes},
     title = {R-unipotent congruences on regular semigroups.},
     journal = {Semigroup forum},
     pages = {265--280},
     publisher = {mathdoc},
     volume = {31},
     year = {1985},
     zbl = {0557.20035},
     url = {http://geodesic.mathdoc.fr/item/SF_1985__31_134753/}
}