@article{andjelkovic_perovic_purenovic_blagojevic_nikolic_andjelkovic_bojic_2006,  title={A direct potentiometric titration study of the dissociation of humic acid with selectively blocked functional groups},  volume={31},  ISSN={0100-4670},  url={https://doi.org/10.1590/S0100-46702006000300005},  DOI={10.1590/S0100-46702006000300005},  number={3},  journal={Eclética Química},  publisher={Fundação Editora da Universidade Estadual Paulista Júlio de Mesquita Filho - UNESP},  author={Andjelkovic, T. and Perovic, J. and Purenovic, M. and Blagojevic, S. and Nikolic, R. and Andjelkovic, D. and Bojic, A.},  year={2006},  pages={39–46} }