Aerodynamic Characteristics of Helicopter Rotors; Rotor Contributions to Helicopter Stability Parameters by Edward Seckel and H.C. Curtiss, Jr.Edward Seckel1963EN
In-flight Simulation Study of Decoupled Longitudinal Controls for the Approach and Landing of a STOL Aircraft / Benjamin Feinreich, Edward Seckel, and David R. Ellis.Benjamin. Feinreich1977EN