R. Jones, B. Rey, O. Madani, und W. Greiner. WWW '06: Proceedings of the 15th international conference on World Wide Web, Seite 387--396. New York, NY, USA, ACM, (2006)
M. Codescu, und T. Mossakowski. Algebra and Coalgebra in Computer Science, CALCO'11, Volume 6859 von Lecture Notes in Computer Science, Seite 145-160. Springer, (2011)