@article{GDZPPN001252569, title = {The semigroup of a strongly connected automaton.}, journal = {Semigroup forum}, volume = {14}, year = {1977}, pages = {351-356}, zbl = {0383.20056}, url = {http://dml.mathdoc.fr/item/GDZPPN001252569} }
Oehmke, R.H. The semigroup of a strongly connected automaton.. Semigroup forum, Tome 14 (1977) pp. 351-356. http://gdmltest.u-ga.fr/item/GDZPPN001252569/