@article{SF_1995__50_3_135378,
     author = {C.M. Reis},
     title = {Periodic endomorphisms of a free monoid.},
     journal = {Semigroup forum},
     pages = {193--204},
     year = {1995},
     volume = {50},
     number = {3},
     zbl = {0833.20072},
     url = {http://geodesic.mathdoc.fr/item/SF_1995__50_3_135378/}
}