“Rigid-body modeling and nonlinear state estimation of an X-configuration quadrotor UAV based on the AscTec hummingbird platform” (2026) Natural and Applied Sciences International Journal (NASIJ), 7(1), pp. 140–165. Available at: https://ideapublishers.org/index.php/nasij/article/view/7.1.8 (Accessed: 18 September 2026).