Clerics in the Early Middle Ages: Hierarchies and Functions (First Publication)
Christ as Cleric: The Ordinals of Christ (First Publication)
At Sixes and Sevens
and Eights and Nines: The Sacred Mathematics of Sacred Orders in the Early Middle Ages (Speculum 54, no. 4. Cambridge, Mass., 1979)
The Subdiaconate as a Sacred and Superior Order (First Publication)
Patristic presbyterianism in the Early Medieval Theology of Sacred Orders (Mediaeval Studies 45. Toronto, 1983)
Clerical Liturgical Vestments and Liturgical Colors in the Middle Ages (First Publication)
The Portrait of the Ecclesiastical Officers in the Raganaldus Sacramentary and its Liturgico-Canonical Significance (Speculum 46, no. 3. Cambridge, Mass., 1971.)
Image and Text: The Liturgy of Clerical Ordination in Early Medieval Art (Gesta 22, no. 1. New York, 1983)
Rites and Signs of Conciliar Decisions in the Early Middle Ages (Segni e Riti nella Chiesa Altomedievale occidentale, XXXIII Settimane di Studio del Centro Italiano di Studi sull'Alto Medioevo, Spoleto, 11-17 Aprile 1985. Spoleto, 1987).