World's Helicopters illustrated history of Helicopters Source Book of Vertical Take-Off Aircraft Jolly Green Giants; US Combat Helicopters Mensch durf te leven: profielen van leiderschap en moed Lt generaal der KLu Julius Lucius Zegers British Military Helicopters Strategy for the West Bomber Aircraft of the World Helicopters at war History of Helicopters Marinebeleid in de Tweede Wereldoorlog Military Helicopters