Columbia subject headings:
Harvard subject headings:
Canada. Royal Canadian Navy
Naval convoys.
World War, 1939-1945--Campaigns--Saint Lawrence, Gulf of.
World War, 1939-1945--Canada.
World War, 1939-1945--Naval operations, Canadian.
World War, 1939-1945--Naval operations--Submarine.
Princeton subject headings:
Coast defenses--Canada.
World War, 1939-1945--Campaigns--Atlantic Ocean.
World War, 1939-1945--Naval operations, Canadian.
World War, 1939-1945--Naval operations, German.