Anyone using the USUARIUM datasets in any way and for any purpose is hereby asked to acknowledge the copyright and the source of the data by including the following attribution statement:
Data retrieved from USUARIUM: A Digital Library and Database for the Study of Latin Liturgical History in the Middle Ages and Early Modern Period (http://usuarium.elte.hu) built by Miklós István Földváry et al. at Eötvös Loránd University (Budapest, Hungary), Research Group of Liturgical History—from 2015 onwards.