Columbia subject headings:
Harvard subject headings:
Pennsylvania Avenue (Washington, D.C.)
Presidents--Dwellings--Security measures--Washington (D.C.)
Terrorism--Washington (D.C.)--Prevention.
White House (Washington, D.C.)--Security measures.
Princeton subject headings:
Pennsylvania Avenue (Washington, D.C.)
Presidents--Dwellings--Security measures--Washington (D.C.).
Terrorism--Washington (D.C.)--Prevention.
White House (Washington, D.C.)--Security measures.