^Salvador Miranda. "Cardinals of the 13th Century". The Cardinals of the Holy Roman Church. Archived from the original on 15 April 2019. Retrieved 11 February 2019.
^Rudolf Hüls (1977), Kardinal, Klerus und Kirchen Roms: 1049–1130(in German), Tübingen: Max Niemeyer 1977, pp. 151-152, states that Hugo of Alatri was created a cardinal at the latest in 1116. There is no authority for the date 1105.
^H.W.Klewitz, p. 128 no. 31; Brixius, p. 36 no. 26. His first subscription of the papal bulls took place on 25 February 1114 (Jaffé, p. 478)