On z -submonoids and z -codes M. Madonia; S. Salemi; T. Sportelli — 1991 RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications
Completing codes A. Restivo; S. Salemi; T. Sportelli — 1989 RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications