Modern Air Power Helicopters Sikorsky Aircraft; Defence Illustrated History of Helicopters Warplanes of the world 1918-1939 Edmund Rumpler Konstrukteur und Erfinder Duxford it's first year of war Bader : the man and his men Jane's encyclopedia of Aviation : Volume 1 Jane's encyclopedia of Aviation : Volume 2 Jane's encyclopedia of Aviation : Volume 3 Jane's encyclopedia of Aviation : Volume 4 Jane's encyclopedia of Aviation : Volume 5
