1. Bartetzko, D.: Parallelität und Vererbung beim Programmieren mit Vertrag. Diplomarbeit, Universität Oldenburg (April 1999)
2. Blume, M., McAllester, D.: Sound and complete models of contracts. Journal of Functional Programming (to appear)
3. Carrillo-Castellon, M., Garcia-Molina, J., Pimentel, E., Repiso, I.: Design by contract in Smalltalk. Journal of Object-Oriented Programming 7(9), 23–28 (1996)
4. Cheon, Y.: A runtime assertion checker for the Java Modelling Language. Technical Report 03-09, Iowa State University Computer Science Department (April 2003)
5. Conway, D., Goebel, C.G.: Class:Contract – design-by-contract OO in Perl, http://search.cpan.org/~ggoebel/Class-Contract-1.14/