@article{SF_1976__13_134196,
     author = {M. P. Sch\"utzenberger},
     title = {Sur le produit de concat\'enation non  ambigu.},
     journal = {Semigroup forum},
     pages = {47--76},
     publisher = {mathdoc},
     volume = {13},
     year = {1976},
     zbl = {0373.20059},
     url = {http://geodesic.mathdoc.fr/item/SF_1976__13_134196/}
}