• Shape files infrastructure and nature (railway, roads, water, forest): all originally by OpenStreetMap contributors. Status december 2011
• Protected area boundaries: derived via cultureelerfgoed.nl & kich. Unrestricted use, status 2012
• Additional data for landuse: OSM / Corine land cover, 2006 (eea.europa.eu)
• Mentioned sources combined and exported for each protected area using a script by Michiel1972