Jan van Leeuwen. A Generalisation of Parikh s Theorem in Formal Language Theory. In Jacques Loeckx, editor, Automata, Languages and Programming, 2nd Colloquium, University of Saarbrücken, July 29 - August 2, 1974, Proceedings. Volume 14 of Lecture Notes in Computer Science, pages 17-26, Springer, 1974.
Abstract is missing.