Silvia E. Gordillo Federico Balaguer Catalina Mostaccio Fernando Das Neves Developing GIS Applications with Objects: A Design Patterns Approach. 7-32 1999 3 GeoInformatica 1 db/journals/geoinformatica/geoinformatica3.html#GordilloBMN99 http://dx.doi.org/10.1023/A:1009809511770