Open Source Software: Quality Verification 9th IFIP WG 2.13 International Conference, OSS 2013, Koper-Capodistria, Slovenia, June 25-28, 2013. Proceedings - Petrinja, Etiel; Succi, Giancarlo; Ioini, Nabil El; Sillitti, Alberto (Springer Berlin Heidelberg : Imprint: Springer, 2013)