F. Shi, J. Li, J. Tang, G. Xie, and H. Li. The Semantic Web -- ISWC 2009: 8th International Semantic Web Conference, Chantilly, VA, USA, volume 5823 of Lecture Notes in Computer Science, Springer, Berlin, (2009)
G. Schuh, R. Senderek, and G. Gudergan. Management industrieller Dienstleistungen: Handbuch Produktion und Management 8, chapter 10, Springer Vieweg, Berlin, 2 edition, (2016)
T. Scheffler, R. Roller, and N. Reithinger. Proceedings of the 6th IJCAI Workshop on Knowledge and Reasoning in Practical Dialogue Systems, Pasadena, CA, USA, page 93-98. (2009)