Giancarlo Mauri Gheorghe Paun Mario J. Pérez-Jiménez Grzegorz Rozenberg Arto Salomaa Membrane Computing, 5th International Workshop, WMC 2004, Milan, Italy, June 14-16, 2004, Revised Selected and Invited Papers 3365 2005 3-540-25080-8 Workshop on Membrane Computing Lecture Notes in Computer Science Springer db/conf/membrane/membrane2004.html