Columbia subject headings:
Caspar, Karl, 1879-1956--Catalogs.
Harvard subject headings:
Caspar, Karl, 1879-1956--Catalogues raisonnés.
Caspar, Karl, 1879-1956--Exhibitions.
Princeton subject headings:
Caspar, Karl, 1879-1956--Catalogues raisonnés.
Caspar, Karl, 1879-1956--Exhibitions.