Klaus Reinhardt. A Parallel Context-Free Derivation Hierarchy. In Gabriel Ciobanu, Gheorghe Paun, editors, Fundamentals of Computation Theory, 12th International Symposium, FCT 99, Iasi, Romania, August 30 - September 3, 1999, Proceedings. Volume 1684 of Lecture Notes in Computer Science, pages 441-450, Springer, 1999. [doi]
Abstract is missing.