I. Penkov, and D. Aleksandrov. “Analysis and Study of the Influence of the Geometrical Parameters of Mini Unmanned Quad-Rotor Helicopters to Optimise Energy Saving”. International Journal of Automotive and Mechanical Engineering 14, no. 4 (December 9, 2022): 4730–4746. Accessed May 19, 2024. https://journal.ump.edu.my/ijame/article/view/8011.