1. Enderton, H., A Mathematical Introduction to Logic, New York, Academic Press, 1972
2. Gruber, T., A Translation Approach to Portable Ontologies, Knowledge Acquisition 2, 1993, 199–220
3. Standard Users Manual for the ICAM Function Modeling Method — IDEFO, IEEE draft standard, P1320. 1. 1, 1997
4. Mayer, R. J., Menzel, C., Painter, M., deWitte, P., Blinn, T., Benjamin, P., IDEF3 Process Description Capture Method Report, Wright-Patterson AFB, Ohio, AL/HRGA, 1993
5. Mayer, R., Keen, A., Browne, D., Harrington, S., Marshall, C., Painter, M., Schafrik, F., Huang, J., Wells, M., Hisesh, H., IDEF4 Object-oriented Design Method Report, Wright-Patterson AFB, Ohio, AL/HRGA, 1995