Formal Techniques for Distributed Systems : Joint 13th IFIP WG 6.1 International Conference, FMOODS 2011, and 30th IFIP WG 6.1 International Conference, FORTE 2011, Reykjavik, Island, June 6-9, 2011, Proceedings - Roberto Bruni, Juergen Dingel ((Lecture Notes in Computer Science))