@article{GDZPPN001256831, title = {A note on intersections of free submonoids of a free monoid.}, journal = {Semigroup forum}, volume = {30}, year = {1984}, pages = {183-206}, zbl = {0555.20037}, url = {http://dml.mathdoc.fr/item/GDZPPN001256831} }
Karhumäki, J. A note on intersections of free submonoids of a free monoid.. Semigroup forum, Tome 30 (1984) pp. 183-206. http://gdmltest.u-ga.fr/item/GDZPPN001256831/