Columbia subject headings:
Harvard subject headings:
Admirals--Great Britain--Biography
Biographies.
Hall, William Reginald, 1870-1943.
Spies--Great Britain--Biography.
World War, 1914-1918--Secret service--Great Britain
Princeton subject headings:
Admirals--Great Britain--Biography.
Biographies.
Hall, William Reginald, 1870-1943.
Spies--Great Britain--Biography.
World War, 1914-1918--Secret service--Great Britain.