@article{gubiani_reichert_reinert_gelain_2011,  title={Implications of the variability in soil penetration resistance for statistical analysis},  volume={35},  ISSN={0100-0683},  url={https://doi.org/10.1590/S0100-06832011000500003},  DOI={10.1590/S0100-06832011000500003},  number={5},  journal={Revista Brasileira de Ciência do Solo},  publisher={Sociedade Brasileira de Ciência do Solo},  author={Gubiani, Paulo Ivonir and Reichert, José Miguel and Reinert, Dalvan José and Gelain, Neiva Somavilla},  year={2011},  month={Sep},  pages={1491–1498} }