1. 4Gerdes, R.M. and Hynes, C.S. "Factors Affecting Handling Qualities of a Lift-Fan Aircraft During Steep Terminal Area Approaches," 27th Annual National Forum of the American Helicopter Society, May 1971.
2. 5Rustin, C.G."Piloting Aspects of V/STOL Approach Guidance," AGARD Conference on the Guidance and Control of V/STOL Aircraft and Helicopters at Night and in Poor Visibility, Stuttgart, Germany, May 1974.
3. 6Dukes, T.A., Keane, W.P., and Tsoubanos, C.M. "Image and Superimposed Symbology-An Integrated Display for Helicopters," 29th Annual National Forum of the American Helicopter Society, May 1973.