Columbia subject headings:
Church history--Primitive and early church, ca. 30-600.
Worship in the Bible.
Worship--History--Early church, ca. 30-600.
Harvard subject headings:
Apostolic Fathers--History and criticism.
Bible. Epistles of Paul--Criticism, interpretation, etc.
Christian literature, Early--History and criticism.
Fathers of the church--History and criticism.
Liturgies, Early Christian.
Worship, Early church.
Princeton subject headings: