Columbia subject headings:
Harvard subject headings:
Gays--Germany--Social conditions--Congresses.
Gays--History--Congresses.
Gays--Social conditions--Congresses.
Sexology--Research--History--Congresses.
Princeton subject headings:
Gays--Germany--Social conditions--History--Congresses.
Gays--Social conditions--History--Congresses.
Sexology--Research--History--Congresses.