Martin Glinz Patrick Heymans Requirements Engineering: Foundation for Software Quality, 15th International Working Conference, REFSQ 2009, Amsterdam, The Netherlands, June 8-9, 2009, Proceedings 5512 2009 http://dx.doi.org/10.1007/978-3-642-02050-6 978-3-642-02049-0 REFSQ Lecture Notes in Computer Science Springer db/conf/refsq/refsq2009.html