R. Van Der Straeten, V. Jonckers, and T. Mens. UML 2004 - The Unified Modeling Language, volume 3273 of Lecture Notes in Computer Science, page 305--319. Springer-Verlag, (October 2004)
P. Van Gorp, H. Stenten, T. Mens, and S. Demeyer. UML 2003 - The Unified Modeling Language, volume 2863 of Lecture Notes in Computer Science, page 144--158. Springer-Verlag, (2003)
M. Boger, T. Sturm, and P. Fragemann. Proc. Int'l Conf. eXtreme Programming and Flexible Processes in Software Engineering (XP), page 77--81. (2002)Alghero, Sardinia, Italy.
A. Correa, and C. Werner. Proc. UML 2004 - The Unified Modeling Language, volume 3273 of Lecture Notes in Computer Science, page 173--187. Springer-Verlag, (October 2004)