@article{SF_1971__2_133817,
     author = {O. Steinfeld},
     title = {A remark on intra-regular semigroups.},
     journal = {Semigroup forum},
     pages = {89--89},
     publisher = {mathdoc},
     volume = {2},
     year = {1971},
     zbl = {0236.20051},
     url = {http://geodesic.mathdoc.fr/item/SF_1971__2_133817/}
}