L. Brehm, A. Heinzl, und M. Markus. Proceedings of the 34th Hawaii International Conference on System Sciences, Seite 1-9. University of Hawaii, (2001)
U. Frank, und S. Strecker. ICB Research Report, 31. Institute for Computer Science and Business Information Systems (ICB), Duisburg-Essen University, Germany, (April 2009)