@article{berton_pratt_1997,  title={EVALUATION OF PHOSPHORUS REQUIREMENT BY THE SORPTION ISOTHERM TECHNIQUE IN SOILS AMENDED WITH ORGANIC MATERIALS },  volume={21},  ISSN={0100-0683},  url={https://doi.org/10.36783/18069657rbcs19972005},  DOI={10.36783/18069657rbcs19972005},  number={2},  journal={Revista Brasileira de Ciência do Solo},  publisher={Sociedade Brasileira de Ciência do Solo},  author={BERTON, R. S. and PRATT, P. F.},  year={1997},  pages={199–206} }