Marshall, Katherine, (2005): Finding Global Balance, World Bank Publications. s. 119. Sitat: «His All Holiness is the spiritual leader of 300 million Orthodox Christians worldwide»
Brien, Joanne O.; Palmer, Martin (2007): The Atlas of Religion. University of California Press. ISBN 978-0-520-24917-2. s. 22. Sitat: «There are over 220 million Orthodox Christians worldwide.»
"Eastern Orthodoxy", Encyclopædia Britannica Online. Sitat: «Eastern Orthodoxy, official name, used in British English as well, is Orthodox Catholic Church, one of the three major doctrinal and jurisdictional groups of Christianity.»
Parry, Ken; Melling, David J.; Brady, Dimitri; Griffith, Sidney H.; Healey, John F., red. ([1999] 2017): «Eastern Orthodox», The Blackwell Dictionary of Eastern Christianity. Oxford, UK: Blackwell Publishing Ltd. doi:10.1002/9781405166584. ISBN 978-1-4051-6658-4. s. 170. Sitat: The Eastern Orthodox are the second largest Christian communion, exceeded in members only by the Roman Catholic communion.
