Columbia subject headings:
Art, German--20th century.
Art, Modern--20th century.
Art.
Nebel, Otto, 1892-1973--Bibliography.
Nebel, Otto, 1892-1973.
Harvard subject headings:
Art, German--20th century.
Art, German.
Art, Modern--20th century
Nebel, Otto, 1892-1973.
Princeton subject headings:
Art, German--20th century.
Art, Modern--20th century.
Art.
Nebel, Otto, 1892-1973--Bibliography.
Nebel, Otto, 1892-1973.