@article{batista_melo_gilkes_2016,  title={Microwave Acid Extraction to Analyze K and Mg Reserves in the Clay Fraction of Soils},  volume={40},  ISSN={0100-0683},  url={https://doi.org/10.1590/18069657rbcs20160067},  DOI={10.1590/18069657rbcs20160067},  journal={Revista Brasileira de Ciência do Solo},  publisher={Sociedade Brasileira de Ciência do Solo},  author={Batista, Araína Hulmann and Melo, Vander Freitas and Gilkes, Robert},  year={2016},  pages={e0160067} }