Columbia subject headings:
German literature--Germany--Ruhr (Region)--20th century--History and criticism.
German literature--Germany--Ruhr (Region)--21st century--History and criticism.
Harvard subject headings:
German literature--Germany--Ruhr (Region)--20th century--History and criticism.
German literature--Germany--Ruhr (Region)--21st century--History and criticism.
Princeton subject headings:
German literature--Germany--Ruhr (Region)--20th century--History and criticism.
German literature--Germany--Ruhr (Region)--21st century--History and criticism.