1. Honeycomb vs. square and cubic models;Brimkov;Electronic Notes in Theoretical Computer Science,2001
2. Geography markup language;Burggraf;Data Science Journal,2006
3. Butler , H. Daly , M. Doyle , A. Gillies , S. Schaub , T. Schmidt , C. 2008 The GeoJSON format specification http://wwwgeojsonorg/geojson-spechtml/
4. ISEA discrete global grids;Carr;Statistical Computing & Statistical Graphics Newsletter,1997
5. de Sousa , L. M. 2006 Algebra de mapas em grelhas hexagonais