1. Elementary Concepts of Topology;Alexandroff,1961
2. What's in an image;Camara,2001
3. An algebraic model for spatial objects with indeterminate boundaries;Clementini,1995
4. The egg-yolk representation of regions with indeterminate boundaries;Cohn,1995
5. Qualitative spatial representation and reasoning;Cohn;Handb. Knowl. Represent.,2008