@article{SLC_1989_22_a11,
     author = {Giuseppe Pirillo},
     title = {Permutabilit\`a e propriet\`a combinatorie delle parole infinite su un alfabeto finito},
     journal = {S\'eminaire lotharingien de combinatoire},
     year = {1989},
     volume = {22},
     url = {http://geodesic.mathdoc.fr/item/SLC_1989_22_a11/}
}