R. Freund, M. Oswald:
"CD Grammar Systems with Regular Start Conditions";
Talk: International Workshop on Descriptional Complexity of Formal Systems, High Tatras; 2007-07-20 - 2007-07-22; in: "Descriptional Complexity of Formal Systems", V. Geffert, G. Pighizzini (ed.); (2007), ISBN: 978-80-7097-688-3; 69 - 80.