Columbia subject headings:
Harvard subject headings:
Dortmund (Germany)--History.
Dortmund (Germany)--Relations--Germany--Zwickau.
Zwickau (Germany)--History.
Zwickau (Germany)--Relations--Germany--Dortmund.
Princeton subject headings:
Dortmund (Germany)--History.
Dortmund (Germany)--Relations--Germany--Zwickau.
Zwickau (Germany)--History.
Zwickau (Germany)--Relations--Germany--Dortmund.