1. Andreka, A., Nemeti, H., Sain, I.: Algebraic Logic. In: Gabbay, D. (ed.) Handbook of Philosophical Logic. Kluwer, Dordrecht (1997)
2. Lecture Notes in Computer Science;A.G. Cohn,1997
3. Frontiers in AI and Applications;M.T. Escrig,1998
4. Escrig, M.T., Toledo, F.: A Framework Based on CLP Extended with CHRs for Reasoning with Qualitative Orientation and Positional Information. Journal of Visual Languages and Computing 9, 81–101 (1998)
5. Freksa, C., Zimmermann, K.: On Utilization of Spatial Structures for Cognitively Plausible and Efficient Reasoning. In: Proc. IEEE Intl. Conf. on Systems, Man and Cybernetics, pp. 18–21 (1992)