@article{ITA_1980__14_1_39_0,
     author = {De Luca, Aldo},
     title = {On some properties of the syntactic semigroup of a very pure subsemigroup},
     journal = {RAIRO. Informatique th\'eorique},
     pages = {39--56},
     publisher = {EDP-Sciences},
     volume = {14},
     number = {1},
     year = {1980},
     mrnumber = {570037},
     zbl = {0437.20053},
     language = {en},
     url = {http://www.numdam.org/item/ITA_1980__14_1_39_0/}
}