1. Holbxk-Hansen, E., Håndlykken, P. and Nygaard, K. (1975) System Description and the Delta Language. Norwegian Computing Center, Publ. No. 523.
2. Jacobsen, E. E., Kristensen, B. B. and Nowack, P. (1998) Models, domains, and abstractions in software development. Proceedings of International Conference on Technology of Object-Oriented Languages and Systems (TOOLS Asia’98), Bejing, China.
3. Jacobson, I., Booch, G and Rumbaugh, J. (1999) The Unified Development Process. Addison-Wesley.
4. Kristensen, B. B., Madsen O. L., Moller Pedersen, B. and Nygaard, K. (1983) Abstraction mechanisms in the BETA programming language. In Proceedings of the 10th ACM Symposium. Principles of Programming Languages.
5. Lind, M. (2000) Actions, Functions and Failures in Dynamic Environments. Center for Human Machine Interaction. CHMI-8–00
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