Columbia subject headings:
Riis, Jacob A. (Jacob August), 1849-1914.
United States--Social conditions--1865-1918.
Urbanization--United States.
Harvard subject headings:
Riis, Jacob A. (Jacob August), 1849-1914.
United States--Social conditions--1865-1918.
Urbanization--United States
Princeton subject headings:
Riis, Jacob A. (Jacob August), 1849-1914.
United States--Social conditions--1865-1918.
Urbanization--United States.