Columbia subject headings:
Documentary films--Germany--Duisburg--History and criticism.
Ružička, Werner, 1947---Interviews.
Harvard subject headings:
Documentary films--Germany--History and criticism.
Film festivals--Germany--Duisburg--History.
Ružička, Werner, 1947---Interviews.
Princeton subject headings:
Documentary films--Germany--Duisburg--History and criticism.
Interviews.
Ružička, Werner, 1947---Interviews.