David W. Corne, Pierluigi Frisco, Gheorghe Paun, Grzegorz Rozenberg, Arto Salomaa: Membrane Computing - 9th International Workshop, WMC 2008, Edinburgh, UK, July 28-31, 2008, Revised Selected and Invited Papers. Lecture Notes in Computer Science 5391, Springer 2009, ISBN 978-3-540-95884-0