por Canadian Institute of Surveying | Association of Dominion Land Surveyors | Canadian Institute of Surveying and Photogrammetry | Canadian Institute of Surveying and Mapping.
por American Congress on Surveying and Mapping.
por American Congress on Surveying and Mapping | American Society of Photogrammetry.
por Colegio Oficial de Ingenieros Técnicos en Topografía (Madrid).