Zohra Bellahsene, Akmal B. Chaudhri, Erhard Rahm, Michael Rys, Rainer Unland: Database and XML Technologies, First International XML Database Symposium, XSym 2003, Berlin, Germany, September 8, 2003, Proceedings. Lecture Notes in Computer Science 2824, Springer 2003, ISBN 3-540-20055-X