1. Design, development and flight demonstration of the loads and stability characteristics of bearingless main rotor;Dixon;U.S.A. AVRADCOM-TR-80-D3,1980
2. Design considerations for bearingless main rotor hubs;Bousman,1983
3. The bending vibrations of a twisted rotating beam;Targoff,1957
4. Natural frequencies in bending of twisted rotating blades;Isakson;NASA TN D-371,1960
5. Natural frequencies in coupled bending and torsion of twisted rotating and non-rotating blades;Isakson;NASA CR-65,1964