@article{SF_1971__2_251454,
     author = {B.M. Schein},
     title = {Erratum to },
     journal = {Semigroup forum},
     pages = {376--376},
     publisher = {mathdoc},
     volume = {2},
     year = {1971},
     zbl = {0232.20130},
     url = {http://geodesic.mathdoc.fr/item/SF_1971__2_251454/}
}