BBC: Factfile: Roman Catholics around the world april 2005. «The Roman Catholic Church - the largest branch of Christianity - says there are a total of 1.086 billion baptised members around the globe. This figure is expected to exceed 1.1 billion in 2005, with rapid growth in Africa and Asia. However, there are no reliable figures for the number of practising Catholics worldwide.»
«The teaching office» Katekismen til den katolske kirke, Vatican.va «889 In order to preserve the Church in the purity of the faith handed on by the apostles, Christ who is the Truth willed to confer on her a share in his own infallibility.» 30. august 2011
