1. Algebra of Programming;Bird,1996
2. Rudolf Berghammer, Thomas Gritzner, Gunther Schmidt, Prototyping relational specifications using higher-order objects, in: Jan Heering, Kurt Meinke, Bernhard Möller, Tobias Nipkow (Eds.), Higher-Order Algebra, Logic, and Term Rewriting, Lecture Notes in Computer Science, vol. 816, Springer-Verlag, 1994, pp. 56–75. 1st Int’l Workshop, HOA ’93 in Amsterdam.
3. Rudolf Berghammer, Armando Martín Haeberer, Gunther Schmidt, Paulo A.S. Veloso, Comparing two different approaches to products in abstract relation algebra, in: Nivat et al. [9, pp. 167–176], Proc. 3rd Int’l Conf. Algebraic Methodology and Software Technology (AMAST ’93), University of Twente, Enschede, The Netherlands, June 21–25, 1993. For references from [3,4,8].
4. Rudolf Berghammer, Gunther Schmidt, RelView—a computer system for the manipulation of relations (Notes to a system demonstration), in: Nivat et al. [9, pp. 403–404], Proc. 3rd Int’l Conf. Algebraic Methodology and Software Technology (AMAST ’93), University of Twente, Enschede, The Netherlands, June 21–25, 1993. For references from [3,4,8].
5. Rudolf Berghammer, Gunther Schmidt, Hans Zierer, Symmetric quotients, Technical Report TUM-INFO 8620, Technische Universität München, Institut für Informatik, 1986.