Columbia subject headings:
Harvard subject headings:
Europe, Central--Politics and government--Congresses.
Gersau (Switzerland)--History--Congresses.
Gersau (Switzerland)--Politics and government--Congresses.
Princeton subject headings:
Europe, Central--Politics and government--Congresses.
Gersau (Switzerland)--History--Congresses.
Gersau (Switzerland)--Politics and government--Congresses.