1. Dick Judith P. (1992) A conceptual, case-relation representation of text for intelligent retrieval. Toronto: Computer Systems Research Institute, University of Toronto, 1992. Technical Report CSRI-265.
2. Esch, John W. (1993) “Contexts as white box concepts,” Supplementary Papers First International Conference on Conceptual Structures. Quebec: Laval University, August, 1993. 17–28.
3. Somers, Harold L. (1987) Valency and case in computational linguistics. Edinburgh: Edinburgh Univ. Press. 1987.
4. Sowa, John F. (1984) Conceptual structures: information processing in mind and machine. Reading, MA.: Addison-Wesley, 1984.
5. Sowa, John F.(1988) “Conceptual graph notation”, Proceedings, Third Annual Workshop on Conceptual Graphs. Menlo Park, CA. August, 1988, 2-1-2-22.