1. Draper, J W and Kuhn, R E “Investigation of the Aerodynamic Characteristics of a Model Wing-Propeller Combination and of the Wing and Propeller Separately at Angles of Attack up to 90°,” NACA Rep 1263, 1956
2. Kirby, R H “Stability and Control of Propeller-Driven Transport VTOL Aircraft,” Proceedings of the XIII Annual National Forum, American Helicopter Society, 1957
3. Zimmerman, C H “Some Stability Problems of Vertically Rising Aircraft,” Proceedings of the Second Annual Western Forum, American Helicopter Society, 1955
4. Stepniewski, W Z “A Comparison Between Pay-Load Capabilities of VTOL and Conventional Aircraft,” Engineering Review, August, 1956
5. Stepniewski, W Z and Mallen, Joseph “Evaluation of VTOL Systems Suitable for Transport Applications,” Aeronautical Engineering Review, September, 1957