Union of Utrecht of the Old Catholic Churches
- History, information on international congresses and the International Bishops' Conference, documents, news items. In English and German.
- http://www.utrechter-union.org/

The Old Catholic Churches of the Union of Utrecht
- Historical overview. The members of the Union of Utrecht, except for the Polish National Catholic Church, have been in full communion with the churches of the Anglican Communion since 1931.
- http://www.tec-europe.org/partners/Utrecht_partners.htm