Columbia subject headings:
Christianity and other religions--Islam--Congresses.
Germany--Religion--20th century--Congresses.
Islam--Relations--Christianity--Congresses.
Turkey--Religion--20th century--Congresses.
Harvard subject headings:
Christianity and other religions--Islam--Congresses
Germany--Religion--20th century--Congresses.
Islam--Relations--Christianity--Congresses
Turkey--Religion--20th century--Congresses.
Princeton subject headings: