(Inggris) Vatican I, Session 4, 1870. Decrees of the First Vatican Council, SESSION 4: 18 July 1870 - First Dogmatic Constitution on the Church of Christ. Daily Catholic Online edition retrieved on September 1, 2006.
(Inggris) Encyclopedia of Religion and Society, William H. Swatos, Jr. Editor Lutheranism Hartford Institute for Religion Research, Hartford Seminary. Diakses pada 4 September 2006.
(Inggris) The first descriptions of the bishop (episcopus) Diarsipkan 2011-08-06 di Wayback Machine. and of ordination by apostolic succession in the New Testament Diarsipkan 2011-08-11 di Wayback Machine.
(Inggris) The first descriptions of the bishop (episcopus) Diarsipkan 2011-08-06 di Wayback Machine. and of ordination by apostolic succession in the New Testament Diarsipkan 2011-08-11 di Wayback Machine.
