* Official website of the [http://www.vatican.va Vatican]

* [http://www.zenit.org Zenit - The World Seen from Rome] - An excellent source of news and reflection for worlds events from a Roman Catholic perspective.

* [http://www.papalencyclicals.net/Leo13/l13praec.htm PRAECLARA GRATULATIONIS PUBLICAE] THE REUNION OF CHRISTENDOM Encyclical Letter of Pope Leo XIII June 20, 1894

* Dr. [[w:Anthony Kenny|Anthony Kenny]]. ''[http://entertainment.timesonline.co.uk/tol/arts_and_entertainment/the_tls/article5843760.ece Follies of Roman Catholicism: How the Catholic Church failed to save itself from the Reformation].'' '''TIMESONLINE.''' (From The Times Literary Supplement), March 4, 2009.