Columbia subject headings:
Photography--United States.
Postcards--United States.
United States--Social life and customs--1865-1918--Pictorial works.
Harvard subject headings:
Photography--United States--History
Postcards--United States.
United States--Pictorial works.
United States--Social life and customs--1865-1918--Pictorial works.
Princeton subject headings:
Postcards--United States.
United States--Description and travel.
United States--Pictorial works.
United States--Social life and customs--1865-1918--Pictorial works.