External Sources:
- THE LAST THINGS by George Eldon Ladd
- FOUR VIEWS ON THE BOOK OF REVELATION Contributors – Kenneth Gentry Jr., Sam Hamstra Jr., C. Marvin Pate
- THE CITY OF GOD by St. Augustine
- DICTIONARY OF BIBLICAL IMAGERY General Editors: Leland Ryken, James Wilhoit, Tremper Longman III
- REVELATION by Craig R. Koester
- THE REVELATION OF ST. JOHN: An Introduction and Commentary (Tyndale New Testament Commentaries) by Leon L. Morris