Columbia subject headings:
Harvard subject headings:
Historic sites--Law and legislation--Washington (D.C.)
Memorials--Law and legislation--Washington (D.C.)
National parks and reserves--Law and legislation--United States
Wild and scenic rivers--Law and legislation--United States.
Princeton subject headings:
Historic sites--Law and legislation--Washington (D.C.).
Memorials--Law and legislation--Washington (D.C.).
National parks and reserves--Law and legislation--United States.
Wild and scenic rivers--Law and legislation--United States.