Cristian S. Calude, André Nies, Ludwig Staiger, Frank Stephan. Universal Recursively Enumerable Sets of Strings. In Masami Ito, Masafumi Toyama, editors, Developments in Language Theory, 12th International Conference, DLT 2008, Kyoto, Japan, September 16-19, 2008. Proceedings. Volume 5257 of Lecture Notes in Computer Science, pages 170-182, Springer, 2008. [doi]
Abstract is missing.