Columbia subject headings:
Harvard subject headings:
Hoodlums--Germany--Cologne--History--21st century.
Hoodlums--Germany--History--21st century.
Right-wing extremists--Germany--History--21st century.
Soccer--Germany--Cologne--History--21st century.
Soccer--Germany--History--21st century.
Sports--Germany--Cologne--History--21st century.
Sports--Social aspects--Germany--History--21st century.
Princeton subject headings:
Hoodlums--Germany--Cologne--History--21st century.
Hoodlums--Germany--History--21st century.
Right-wing extremists--Germany--History--21st century.
Soccer--Germany--Cologne--History--21st century.
Soccer--Germany--History--21st century.
Sports--Germany--Cologne--History--21st century.
Sports--Social aspects--Germany--History--21st century.