Columbia subject headings:
Landschaftsverband Rheinland--History--Congresses.
North Rhine-Westphalia (Germany)--Cultural policy--History--20th century--Congresses.
North Rhine-Westphalia (Germany)--History--20th century--Congresses.
Harvard subject headings:
Landschaftsverband Rheinland--History--Congresses.
North Rhine-Westphalia (Germany)--Cultural policy--History--20th century--Congresses.
North Rhine-Westphalia (Germany)--History--20th century--Congresses.
Rhine Province (Germany)--Cultural policy--History--20th century--Congresses.
Princeton subject headings:
Landschaftsverband Rheinland--History--Congresses.
North Rhine-Westphalia (Germany)--Cultural policy--History--20th century--Congresses.
North Rhine-Westphalia (Germany)--History--20th century--Congresses.
Rhine Province (Germany)--Cultural policy--History--20th century--Congresses.