The Hansa-Brandenburg W.11 was a fighterfloatplane built in Germany in 1917 as a more powerful version of the KDW. Similar in general configuration to its predecessor, the W.11 shared the same unusual interplane strut arrangement, and featured fins above and below the fuselage. Only three examples were built.
Herris, Jack (2012). German Seaplane Fighters of WWI: A Centennial Perspective on Great War Seaplanes. Great War Aviation Centennial Series. Vol. 2. Charleston (S.C.): Aeronaut Books. ISBN978-1-935881-09-4.
Owers, Colin A. (2015). Hansa-Brandenburg Aircraft of WWI: Volume 2–Biplane Seaplanes. Great War Aviation Centennial Series. Vol. 18. n.p.: Aeronaut Books. ISBN978-1-935881-32-2.