The Baltimore Sabotage Cell : German agents, American traitors, and the U-boat Deutschland during Wo

Messimer, Dwight R., 1937-
Annapolis, Maryland : Naval Institute Press, [2015]

The dark invader; wartime reminiscences of a German naval intelligence officer

Rintelen, Franz von, 1878-1949.
New York : The Macmillan company, [1933]

Dark invasion : 1915: Germany's secret war and the hunt for the first terrorist cell in America

Blum, Howard, author.
New York : Harper, [2014]
First Edition.

The German secret service in America

Jones, John Price, 1877-1964.
Boston : Small, Maynard & company, [1918]

Germany's covert war in the Middle East : espionage, propaganda and diplomacy in World War I

Prüfer, Curt Max, 1881-1959, author.
London : I.B. Tauris & Co. Ltd., 2018.

One against England; the death of Lord Kitchener and the plot against the British fleet

Carl, Ernst.
New York : E. P. Dutton, [1935]

SECRET SERVICES, 1918-1939 their development in britain, germany, and russia.

ANDREW SANGSTER, AUTHOR.
[S.l.] : CAMBRIDGE SCHOLARS PUBLIS, 2020.

Steinhauer, the Kaiser's master spy; the story as told by himself

Steinhauer, Gustav.
London : John Lane, [1930]