@article{raij_1973,  title={Determinação do ponto de carga zero em solos},  volume={32},  ISSN={0006-8705},  url={https://doi.org/10.1590/S0006-87051973000100018},  DOI={10.1590/S0006-87051973000100018},  number={unico},  journal={Bragantia},  publisher={Instituto Agronômico de Campinas},  author={Raij, Bernardo van},  year={1973},  pages={337–347} }