1. Firestone, J. 2004. Knowledge Management Metrics Development: A Technical Approach. Published on-line by Executive Information Systems, Inc. http://www.dkms.com/ at: http://www.dkms.com/papers/kmmeasurement.pdf, downloaded 2004-10-02
2. Ford, G. 2004. Measurement Theory for Software Engineers, Published on-line by R.S. Pressman & Associates, Inc. http://www.rspa.com/ at: http://www2.umassd.edu/SWPI/curriculummodule/em9ps/em9.part3.pdf, downloaded 2004-09-24
3. García Martínez, R. & Britos, P. 2004 Expert System Engineering, Nueva Librería Ed. Buenos Aires
4. Kang, Y. & Bahieel, T. 1990. A Tool for Detecting Expert Systems Errors. AI Expert, 5(2): 42–51.
5. Menzies, T. & Cukic, B. 1999. On the Sufficiency of Limited Testing for Knowledge Based Systems. Proceedings of the 11th IEEE International Conference on Tools with Artificial Intelligence, Pages 431–440.