Francisco Escolano Mario Vento Graph-Based Representations in Pattern Recognition, 6th IAPR-TC-15 International Workshop, GbRPR 2007, Alicante, Spain, June 11-13, 2007, Proceedings GbRPR Lecture Notes in Computer Science 4538 Springer 2007 978-3-540-72902-0 db/conf/gbrpr/gbrpr2007.html