@article{GDZPPN001251856, title = {Sch\"utzenberger groups and Chebyshev polynomials.}, journal = {Semigroup forum}, volume = {12}, year = {1976}, pages = {301-306}, zbl = {0354.20052}, url = {http://dml.mathdoc.fr/item/GDZPPN001251856} }
Magill, K.D. jr.; Schanuel, S. Schützenberger groups and Chebyshev polynomials.. Semigroup forum, Tome 12 (1976) pp. 301-306. http://gdmltest.u-ga.fr/item/GDZPPN001251856/