2008, Article in monograph or in proceedings (Mackie, I.; Plump, D. (ed.), Proceedings of the Fourth International Workshop on Computing with Terms and Graphs (TERMGRAPH 2007), pp. 93-108)

2006, Article in monograph or in proceedings (Kohlhase, Michael (ed.), Mathematical Knowledge Management: 4th International Conference, MKM 2005, Bremen, Germany, July 15-17, 2005, Revised Selected Papers, pp. 315-329)