Columbia subject headings:
Fortification--United States.
United States--Defenses.
United States. War Department--Appropriations and expenditures.
Harvard subject headings:
Fortification--United States
United States--Defenses.
United States. Army. Corps of Engineers.
United States. War Department--Appropriations and expenditures.
Princeton subject headings:
Fortification--United States.
United States--Defenses.
United States. War Department--Appropriations and expenditures.