Lock on no 6 Aircraft Photo File, AH-1S Cobra Lock on no 13 Aircraft Photo File, Mi-24W Hind E Gunship Wessex Schiphol Amsterdam stationsgebouwcomplex illustrated guide to Military Helicopters Vietnam Helicopter Handbook Helicopters at war, a pictorial history Helicopter; History, Piloting and how it Flies Dragonflies; The Story of Helicopters and Autogiros Igor Sikorsky; His Three Careers in Aviation Helicopters (EDUCATIEF) Helicopters and Autogiros; A History of Rotating-wing and V/STOL Aviation