Columbia subject headings:
Ophey, Walter, 1882-1930--Catalogues raisonnés.
Harvard subject headings:
Art, German--20th century.
Ophey, Walter, 1882-1930--Catalogues raisonnés.
Princeton subject headings:
Art, German--20th century.
Art, German.
Ophey, Walter, 1882-1930--Catalogues raisonnés.