Columbia subject headings:
Gustav II Adolf, King of Sweden, 1594-1632.
Thirty Years' War, 1618-1648--Campaigns--Germany--Early works to 1800.
Harvard subject headings:
Thirty Years' War, 1618-1648--Campaigns--Germany
Thirty Years' War, 1618-1648--Campaigns--Germany--Early works to 1800.
Princeton subject headings: