Columbia subject headings:
Merchant marine--United States.
United States. Shipping Board.
World War, 1914-1918--Law and legislation--United States.
Harvard subject headings:
Merchant marine--United States
United States. Shipping Board.
World War, 1914-1918--Law and legislation--United States
Princeton subject headings:
Merchant marine--United States.
United States. Shipping Board
World War, 1914-1918--Law and legislation--United States.