Xu, Xiongshi, Keigo Watanabe, and Isaku Nagai. 2021. “Backstepping Control for a Tandem Rotor UAV Robot With Two 2-DOF Tiltable Coaxial Rotors”. Journal of Robotics and Control (JRC) 2 (5):413-20. https://doi.org/10.18196/jrc.25116.