Raul-Cristian Roman Radu-Emil Precup Emil M. Petriu Radu-Codrut David Elena-Lorena Hedrea Alexandra-Iulia Szedlak-Stînean First-Order Active Disturbance Rejection-Virtual Reference Feedback Tuning Control of Tower Crane Systems. 137-142 2020 ICSTCC https://doi.org/10.1109/ICSTCC50638.2020.9259632 conf/icstcc/2020 db/conf/icstcc/icstcc2020.html#RomanPPDHS20