@article{SF_1976__13_134224,
     author = {K. H. Kim and F. Roush},
     title = {General mutants in semigroups.},
     journal = {Semigroup forum},
     pages = {297--300},
     publisher = {mathdoc},
     volume = {13},
     year = {1976},
     zbl = {0354.20050},
     url = {http://geodesic.mathdoc.fr/item/SF_1976__13_134224/}
}