@article{GDZPPN001264001,
title = {Periodic endomorphisms of a free monoid.},
journal = {Semigroup forum},
volume = {51},
year = {1995},
pages = {193-204},
zbl = {0833.20072},
url = {http://dml.mathdoc.fr/item/GDZPPN001264001}
}
Reis, C.M. Periodic endomorphisms of a free monoid.. Semigroup forum, Tome 51 (1995) pp. 193-204. http://gdmltest.u-ga.fr/item/GDZPPN001264001/