The modules 2003 (“National Identity”) and 2004 (“Citizenship”) of the International Social Survey Programme were conducted in the Netherlands as a stand-alone postal survey at the Free University Amsterdam [VUA] (Faculty of Social Sciences, Department of Social Research Methodology) by Harry B.G. Ganzeboom [principal investigator] and Elsbeth de Groot [fieldwork manager]. As of 2005, VUA has taken over the Dutch national membership for the Netherlands, formerly held by the Social and Cultural Planning Office [SCP] in The Hague, with Jos Becker as principal investigators. Funding for the 2004-2005 data collection was equally supplied by the SCP and the VUA.
Note that this dataset is more elaborate than the Dutch part of the international ISSP file, archived at GESIS - Leibniz Institute for the Social Sciences, Cologne, Germany.