@article{BSMF_1965__93__209_0,
     author = {Sch\"utzenberger, M.P.},
     title = {Sur certains sous-mono{\"\i}des libres},
     journal = {Bulletin de la Soci\'et\'e Math\'ematique de France},
     pages = {209--223},
     publisher = {Soci\'et\'e math\'ematique de France},
     volume = {93},
     year = {1965},
     doi = {10.24033/bsmf.1623},
     mrnumber = {32 #7666},
     zbl = {0149.02601},
     language = {fr},
     url = {http://www.numdam.org/articles/10.24033/bsmf.1623/}
}