Andrews 1999, pp. 75–76 and 258. See also Alberzoni 2004, pp. 293–294. Andrews, Frances (1999). The Early Humiliati. Cambridge University Press. Alberzoni, Maria Pia (2004). "Quiddam Minus Catholicum Sapiebat: Consuetudines and Rule among the Humiliati of the Milanese House of the Brera". In Frances Andrews; Christoph Egger; Constance M. Rousseau (eds.). Pope, Church and City: Essays in Honour of Brenda M. Bolton. Brill. pp. 287–308. doi:10.1163/9789047406082. ISBN9789047406082.
Kaeppeli 1962. Kaeppeli, Thomas (1962). "Gerardus Novariensis auteur de la Somme "Ne transgrediaris"". Recherches de théologie ancienne et médiévale. 29: 294–297. JSTOR26187650.