* {{Oxford Dictionary of Byzantium | ad = Paul A. | soyadı = Hollingsworth | başlık = Gregory | sayfalar = 875}}
* {{citeKitap bookkaynağı | editor1-last=Martindale | editor1-first=John Robert | editor2-last=Jones | editor2-first=Arnold Hugh Martin | editor3-last=Morris | editor3-first=J. | title=The Prosopography of the Later Roman Empire, Volume III: A.D. 527–641 |year=1992 | location=Cambridge, United Kingdom | publisher=Cambridge University Press|isbn=978-0-521-20160-5 | url=http://books.google.com/books?id=ElkwedRWCXkC}}
* {{Web kaynağı | url = http://www.roman-emperors.org/gregory.htm | title = Gregory (646-47 A.D.) | last = Moore | first = R. Scott | work = [[De Imperatoribus Romanis]] | year = 1999 | accessdate = 17 June 2012 | arşivurl = http://web.archive.org/web/20150317175938/http://www.roman-emperors.org/gregory.htm | arşivtarihi = 17 Mart 2015}}
* {{citeKitap bookkaynağı | last=Pringle | first=Denys | title=The Defence of Byzantine Africa from Justinian to the Arab Conquest: An Account of the Military History and Archaeology of the African Provinces in the Sixth and Seventh Century | location=Oxford, United Kingdom | publisher=British Archaeological Reports | year=1981 | isbn=0-86054-119-3 | url=http://books.google.com/books?id=4DIjAQAAIAAJ}}
