Columbia subject headings:
Helm, John F., 1900-1972--Catalogues raisonnés.
Helm, John F., 1900-1972--Exhibitions.
Printmakers--Kansas--Manhattan--Exhibitions.
Prints--Kansas--Manhattan--Exhibitions.
Harvard subject headings:
Helm, John F., 1900-1972--Catalogues raisonnés.
Helm, John F., 1900-1972--Exhibitions.
Printmakers--Kansas--Manhattan--Exhibitions.
Prints--Kansas--Manhattan--Exhibitions.
Princeton subject headings: