Columbia subject headings:
Boulder dam.
Mississippi River--Floods.
Muscle Shoals (Ala.)
Protectionism.
Saint Lawrence River.
Tariff--Great Britain.
Harvard subject headings:
Floods--Mississippi River
Hoover Dam (Ariz. and Nev.)
Muscle Shoals (Ala.)
Protectionism.
Saint Lawrence River.
Tariff--Great Britain.
Princeton subject headings: