Catholic Encyclopedia: St. Ludger - Also known as St. Lüdiger, or Liudger. Biography of this missionary, the first bishop of Munster, who died in 809. www.newadvent.org/cathen/09415a.htm
Lives of the Saints: St. Ludger - Entry for this bishop of Munster, Apostle of Saxony, from Alban Butler's Lives of the Saints. www.ewtn.com/library/MARY/LUDGER.HTM
Ludger of Utrecht - Hagiographical essay, with links to other saints with whom Ludger is associated. users.erols.com/saintpat/ss/0326.htm#ludg
