Columbia subject headings:
Agriculture--United States--History--20th century--Pictorial works.
Allen, J. C. (John Calvin), 1881-1976.
Family farms--United States--History--20th century--Pictorial works.
Farm life--United States--History--20th century--Pictorial works.
Farm life--United States--History--Sources.
Photographers--United States--Biography.
Harvard subject headings:
Agriculture--United States--History--20th century--Pictorial works.
Allen, J. C. (John Calvin), 1881-1996.
Family farms--United States--History--20th century--Pictorial works.
Farm life--United States--History--20th century--Pictorial works.
Farm life--United States--History--Sources.
Photographers--United States--Biography
Princeton subject headings:
Agriculture--United States--History--20th century--Pictorial works.
Allen, J. C. (John Calvin), 1881-1996.
Family farms--United States--History--20th century--Pictorial works.
Farm life--United States--History--20th century--Pictorial works.
Farm life--United States--History--Sources.
Photographers--United States--Biography.