Nimbro-OP2X: Affordable Adult-Sized 3D-Printed Open-Source Humanoid Robot for Research. - Ficht, Grzegorz; Farazi, Hafez; Rodriguez, Diego; Pavlichenko, Dmytro; Allgeuer, Philipp; Brandenburger, André; Behnke, Sven (Int. J. Humanoid Robotics, 2020)