Columbia subject headings:
Catholic Church--Relations--Orthodox Eastern Church.
Holy Spirit--Procession--History of doctrines--Middle Ages, 600-1500.
Orthodox Eastern Church--Doctrines--History.
Orthodox Eastern Church--Relations--Catholic Church.
Trinity--History of doctrines--Middle Ages, 600-1500.
Harvard subject headings:
Church history--Middle Ages, 600-1500
Holy Spirit--Procession--History of doctrines--Middle Ages, 600-1500.
Trinity--History of doctrines--Middle Ages, 600-1500.
Princeton subject headings:
Church history--Middle Ages, 600-1500.
Holy Spirit--Procession--History of doctrines--Middle Ages, 600-1500.
Trinity--History of doctrines--Middle Ages, 600-1500.