Peter Sawyer Barbara Paech Patrick Heymans Requirements Engineering: Foundation for Software Quality, 13th International Working Conference, REFSQ 2007, Trondheim, Norway, June 11-12, 2007, Proceedings REFSQ Lecture Notes in Computer Science 4542 Springer 2007 978-3-540-73030-9 db/conf/refsq/refsq2007.html