Blech، Benjamin؛ Doliner, Roy. (2008). The Sistene Secrets. New York, NY: HarperCollins Publishers. ص. 106. ISBN:978-0-06-146904-6. The term 'terrible' was first applied by Julius himself to Michaelangelo, and only later to the Pope by others: Pastor, VI, pp. 214–215.
Conradus Eubel, Hierarchia catholica medii aevi, sive Summorum pontificum, S.R.E. cardinalium, ecclesiarum antistitum series, https://archive.org/details/hierarchiacathol02eubeuoft, editio altera, Tomus II Monasterii, 1913, p.16, no. 2
