Bittner, M., Hoffmann, M., Kühn, N. and Weber, M. (2004). Requirements for Requirements Management Tools. Proc. Requirements Engineering Conference, 12th IEEE International (RE'04)2. IEEE Computer Society, 301-308.
Kammüller, F. and Sanders, J. (2005). Idempotent Relations in Isabelle/HOL. Theoretical Aspects of Computing - ICTAC 2004: First International Colloquium, Guiyang, China. Springer, 310-324.
Kammüller, F. and Sanders, J. W. (2004). Heuristics for Refinement Relations. Proc. Second International Conference on Software Engineering and Formal Methods (SEFM'04). IEEE Computer Society, 292-299.