A ...-calculus with an algorithmic ... . G. Longo; M. Venturini Zilli — 1980 Archiv für mathematische Logik und Grundlagenforschung
Complexity of theorem-proving procedures : some general properties G. Longo; M. Venturini Zilli — 1974 RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications