Columbia subject headings:
Direct democracy--Germany--Congresses.
Direct democracy--Switzerland--Congresses.
Political participation--Germany--Congresses.
Political participation--Switzerland--Congresses.
Referendum--Germany--Congresses.
Referendum--Switzerland--Congresses.
Harvard subject headings:
Direct democracy--Germany--Congresses.
Direct democracy--Switzerland--Congresses.
Political participation--Germany--Congresses.
Political participation--Switzerland--Congresses.
Referendum--Germany--Congresses.
Referendum--Switzerland--Congresses.
Princeton subject headings:
Direct democracy--Germany--Congresses.
Direct democracy--Switzerland--Congresses.
Political participation--Germany--Congresses.
Political participation--Switzerland--Congresses.
Referendum--Germany--Congresses.
Referendum--Switzerland--Congresses.