1. Principles of Helicopter Aerodynamics;Leishman,2006
2. The wake geometry of a hovering helicopter rotor and its influence on rotor performance;Landgrebe;J. Am. Helicopter Soc.,1972
3. The wake of a small-scale rotor in forward flight using flow visualization;Ghee;J. Am. Helicopter Soc.,1995
4. Rotor tip vortex geometry measurements using the wide-field shadowgraph technique;Norman;J. Am. Helicopter Soc.,1987
5. Wide-field shadowgraph flow visualization of tip vortices generated by a helicopter rotor;Parthasarathy,1985