Artur Jez, Alexander Okhotin. Conjunctive Grammars over a Unary Alphabet: Undecidability and Unbounded Growth. In Volker Diekert, Mikhail V. Volkov, Andrei Voronkov, editors, Computer Science - Theory and Applications, Second International Symposium on Computer Science in Russia, CSR 2007, Ekaterinburg, Russia, September 3-7, 2007, Proceedings. Volume 4649 of Lecture Notes in Computer Science, pages 168-181, Springer, 2007. [doi]
Abstract is missing.