Klaper, Michael. „Hispania Vetus. Musical-Liturgical Manuscripts from Visigothic Origins to the Franco Roman Transition (9th–12th Centuries)“. Die Musikforschung 62, no. 4 (Dezember 15, 2009): 384–385. Zugegriffen April 18, 2025. https://mf.journals.qucosa.de/mf/article/view/4317.