↑The Catholic Encyclopedia: Pope Gregory IX; and Gaetano Moroni, vol. XXXII p. 257 and vol. LXXXV, p. 261. Timo Bandhold, p. 9, says that only Konrad von Urach is known to have been a committee member and the rest two members of that body are unknown
Sumber
Konrad Eubel, Hierarchia Catholica Medii Aevi, volumen I, 1913
Gaetano Moroni, Dizionario di erudizione storico-ecclesiastica da S. Pietro sino ai nostri giorni Vol. XXXII and vol. LXXXV, Tipografia Emiliana, Venezia, 1840 - 1861