Columbia subject headings:
Catholic Church--Doctrines--History--19th century.
Catholic Church--Doctrines--History--20th century.
Christianity--Philosophy--History--19th century.
Christianity--Philosophy--History--20th century.
Philosophers, Modern--Biography.
Harvard subject headings:
Catholic Church--Doctrines--History--19th century.
Catholic Church--Doctrines--History--20th century.
Christianity
Christianity--Philosophy--History--20th century.
Church history--19th century
Philosophers, Modern--Biography.
Princeton subject headings:
Christianity--Philosophy.