1. A transformation for extracting new descriptors of shape;Blum,1967
2. A method for obtaining skeletons using a quasi-euclidean distance;Montanari;J. ACM,1968
3. Continuous skeletons from digitized images;Montanari;J. ACM,1969
4. Computer representation of planar regions by their skeletons;Pfaltz;Comm. ACM,1967
5. Shape description with the medial axis transformation;Philbrick,1968