Daniel Kirsten. Some Undecidability Results Related to the Star Problem in Trace Monoids. In Christoph Meinel, Sophie Tison, editors, STACS 99, 16th Annual Symposium on Theoretical Aspects of Computer Science, Trier, Germany, March 4-6, 1999, Proceedings. Volume 1563 of Lecture Notes in Computer Science, pages 227-236, Springer, 1999. [doi]
Abstract is missing.