Cezar Câmpeanu, Kai Salomaa, Sheng Yu. Regex and Extended Regex. In Jean-Marc Champarnaud, Denis Maurel, editors, Implementation and Application of Automata, 7th International Conference, CIAA 2002, Tours, France, July 3-5, 2002, Revised Papers. Volume 2608 of Lecture Notes in Computer Science, pages 77-84, Springer, 2002. [doi]
Abstract is missing.