Ralf Lämmel Joost Visser João Saraiva Generative and Transformational Techniques in Software Engineering II, International Summer School, GTTSE 2007, Braga, Portugal, July 2-7, 2007. Revised Papers 5235 2008 978-3-540-88642-6 GTTSE Lecture Notes in Computer Science Springer db/conf/gttse/gttse2007.html