@article{SF_1986__33_134805,
     author = {W. Barit},
     title = {Automorphism invariants for semigroups.},
     journal = {Semigroup forum},
     pages = {219--238},
     publisher = {mathdoc},
     volume = {33},
     year = {1986},
     zbl = {0589.54048},
     url = {http://geodesic.mathdoc.fr/item/SF_1986__33_134805/}
}