Columbia subject headings:
Friedrich, Caspar David, 1774-1840--Criticism and interpretation.
Harvard subject headings:
Friedrich, Caspar David, 1774-1840--Criticism and interpretation.
Princeton subject headings:
Friedrich, Caspar David, 1774-1840--Criticism and interpretation.
Friedrich, Caspar David, 1774-1840--Themes, motives.
Perspective.
Space (Art)