1. Perceptual and cognitive spatial learning;Bedford;Journal of Experimental Psychology: Human Perception and Performance,1993
2. Cognitive skill: Implications for spatial skill in large-scale environments;Chase,1981
3. A comparison of methods for representing topological relationships;Clementini;Information Sciences,1995
4. A small set of formal topological relationships for end-user interaction;Clementini,1993
5. Qualitative and topological relationships in spatial databases;Cui,1993