Rudolf Berghammer, Ali Jaoua, Bernhard Möller: Relations and Kleene Algebra in Computer Science, 11th International Conference on Relational Methods in Computer Science, RelMiCS 2009, and 6th International Conference on Applications of Kleene Algebra, AKA 2009, Doha, Qatar, November 1-5, 2009. Proceedings. Lecture Notes in Computer Science 5827, Springer 2009, ISBN 978-3-642-04638-4