R. Weinreich, T. Ziebermayr, and D. Draheim. Advanced Information Networking and Applications Workshops, 2007, AINAW '07. 21st International Conference, 2, page 570--575. (May 2007)
D. Tsesmetzis, I. Roussaki, I. Papaioannou, and M. Anagnostou. Telecommunications, 2006. AICT-ICIW '06. International Conference on Internet and Web Applications and Services/Advanced International Conference on, page 128. IEEE Computer Society, (February 2006)
O. Thomas, K. Leyking, and M. Scheid. Business Services: Konzepte, Technologien, Anwendungen: 9. Internationale Tagung Wirtschaftsinformatik, 25.–-27. Februar 2009, Wien, 1, page 181--190. Wien, Österreichische Computer Gesellschaft, (2009)