The structure of index sets and reduced indexed grammars R. Parchmann; J. Duske — 1990 RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications
Indexed counter languages J. Duske; M. Middendorf; R. Parchmann — 1992 RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications