AH-1 Huey Cobra Mil Mi-24 Hind UH-1 Iroquois/ AH-1 Hueycobra Guinnes Book of Helicopter fact and feats British Service Helicopters: a pictorial history Attack Helicopters Mi-24 Hind Military Helicopters of the West Helicopters in Action Hunting with Richthofen Human factors in Aviation Cornelis Jacobus Snijders: 1852-1939