1. F.L. Bauer, R. Berghammer, M. Broy, W. Dosch, F. Geiselbrechtinger, R. Gnatz, E. Hangel, W. Hesse, B. Krieg-Brückner, A. Laut, T.A. Matzner, B. Möller, F. Nickl, H. Partsch, P. Pepper, K. Samelson, M. Wirsing, H. Wössner: The Munich project CIP. Volume I: The wide spectrum language CIP-L. Lecture Notes in Computer Science 183. Berlin: Springer 1985
2. F.L. Bauer, B. Möller, H. Partsch, P. Pepper: Formal program construction by transformations — Computer-aided, Intuition-guided Programming. IEEE Transactions on Software Engineering 15, 165–180 (1989)
3. R. Berghammer: A transformational development of several algorithms for testing the existence of cycles in a directed graph. Institut für Informatik der TU München, TUM-I8615
4. NATO ASI Series. Series F: Computer and systems sciences 55;R. Bird,1989
5. R.M. Burstall, J. Darlington: A transformation system for developing recursive programs. J. ACM 24, 44–67 (1977)