Columbia subject headings:
Harvard subject headings:
Nineteen sixty-eight, A.D.
Protest movements--Germany--Cologne--History--20th century.
Student movements--Germany--Cologne--History--20th century.
Princeton subject headings:
Nineteen sixty-eight, A.D.
Protest movements--Germany--Cologne--History--20th century.
Student movements--Germany--Cologne--History--20th century.