- Centre for Research on Direct Democracy (c2d)
http://www.c2d.ch/ - Centre for Direct Democracy Studies
http://www.prawo.uwb.edu.pl/cdds - Zentrum für Demokratie Aarau (ZDA)
http://www.zdaarau.ch/de/index.php - The Initiative and Referendum Institute Europe (IRI Europe)
http://iri-europe.org