Columbia subject headings:
Apologetics--Early works to 1800.
Apologetics--History--Early church, ca. 30-600.
Manichaeism--Controversial literature--Early works to 1800.
Zoroastrianism--Controversial literature--Early works to 1800.
Harvard subject headings:
Apologetics--Early works to 1800
Manichaeism--Controversial literature--Early works to 1800.
Zoroastrianism--Controversial literature--Early works to 1800.
Princeton subject headings: