Columbia subject headings:
Harvard subject headings:
Architecture--Germany--History--20th century
Architecture--Italy--History--20th century
Architecture--Philosophy
Ungers, O. M. (Oswald Mathias)--Criticism and interpretation.
Princeton subject headings:
Architecture--Germany--History--20th century.
Architecture--Italy--History--20th century.
Architecture--Philosophy.
Ungers, O. M. (Oswald Mathias)--Criticism and interpretation.