The quality management models currently applied cover countrywide supra-regional procedures specific to general or continuing education, as well as systems that are regional or specific to particular associations or federations. An outline of the various quality management models in continuing education as of 2006 is given in the publication Quality Models at a Glance (Qualitätsmodelle im Überblick) published by the German Institute for Adult Education – Leibniz Centre for Lifelong Learning (Deutsches Institut für Erwachsenenbildung – Leibniz-Zentrum für Lebenslanges Lernen – DIE). Since 1 January 1977, distance-learning courses provided by private organisers (institutes of distance-learning) must be approved by the state on the basis of the Law on the Protection of Participants in Distance Education (Fernunterrichtsschutzgesetz – R165).