Compressing digital elevation models with wavelet decomposition. - Patrik Ottoson (ScanGIS, 2001)

Retrieval of geographic data using ellipsoidal quadtrees. - Patrik Ottoson (ScanGIS, 2001)

Ellipsoidal quadtrees for indexing of global geographical data. - Patrik Ottoson; Hans Hauska (Int. J. Geogr. Inf. Sci., 2002)