@article{schons_robaina_peiter_2012,  title={Setting efficiency indicators for center pivots},  volume={32},  ISSN={0100-6916},  url={https://doi.org/10.1590/S0100-69162012000300005},  DOI={10.1590/S0100-69162012000300005},  number={3},  journal={Engenharia Agrícola},  publisher={Associação Brasileira de Engenharia Agrícola},  author={Schons, Ricardo L. and Robaina, Adroaldo D. and Peiter, Márcia X.},  year={2012},  month={May},  pages={459–466} }