Columbia subject headings:
Harvard subject headings:
Cinematography--History--20th century.
Motion pictures--History--20th century
Philosophy, German--19th century.
Philosophy, German--20th century.
Simmel, Georg, 1858-1918--Criticism and interpretation.
Sociology--Germany--History--19th century.
Sociology--Germany--History--20th century
Princeton subject headings:
Motion pictures--Social aspects.
Silent films--History and criticism.
Simmel, Georg, 1858-1918.