Columbia subject headings:
Christlich-Demokratische Union Deutschlands (Germany : West)--Party work.
Political participation--Germany--Ruhr (Region)
Political parties--Germany--Ruhr (Region)
Harvard subject headings:
Christlich-Demokratische Union Deutschlands (Germany : West)--Party work.
Political participation--Germany--Ruhr (Region)
Political parties--Germany--Ruhr (Region)
Princeton subject headings: