1. A B+-tree structure for large quadtrees;Abel;Computer Vision, Graphics and Image Processing,1984
2. Efficient processing of window queries in the pyramid data structure;Aref,1990
3. The R∗-tree: An efficient and robust access method for points and rectangles;Beckmann,1990
4. The space efficiency of quadtrees;Dyer;Computer Graphics and Image Processing,1982
5. What's special about spatial: Database requirements for vehicle navigation in geographic space;Egenhofer,1993