S. Pietschmann, M. Voigt, and K. Meissner. Proceedings of the 2009 Fourth International Conference on Internet and Web Applications and Services, page 217--222. Washington, DC, USA, IEEE Computer Society, (2009)
S. Lohmann, J. Kaltz, and J. Ziegler. Models in Software Engineering, volume 4364 of Lecture Notes in Computer Science, Springer Berlin Heidelberg, (2007)