1. Basic Topology;Armstrong,1983
2. Simple points, topological numbers, and geodesic neighborhoods in cubic grids;Bertrand;Pattern Recognition Letters,1994
3. On P-simple points;Bertrand;Comptes-Rendus de l’Académie des Sciences de Paris, Série I,1995
4. A Boolean characterization of three-dimensional simple points;Bertrand;Pattern Recognition Letters,1996
5. Topological methods;Björner,1995