1. The VTOL approach and landing technology (VALT) CH-47 research system;Kelly;NASA TP-1436,1979
2. A parametric analysis of visual approaches for helicopters;Moen;NASA TN D-8275,1976
3. Simulation and flight studies of an approach profile indicator for VTOL aircraft;Moen;NASA TN D-8051,1975
4. A technique using a nonlinear helicopter model for determining trims and derivatives;Ostroff;NASA TN D-9159,1976
5. Digital flight control design for a tandem-rotor helicopter;Stengel;Automatica,1978