Apgar, Blair. 2024. «Visualizing the Reform: Examining Modena Cathedral’s Porta Dei Principi for Traces of the Gregorian Reform». I Quaderni Del m.æ.S. - Journal of Mediæ Ætatis Sodalicium 22 (1):63-81. https://doi.org/10.6092/issn.2533-2325/19498.