@article{perez_leite_coelho_2006,  title={Activated sludge morphology characterization through an image analysis procedure},  volume={23},  ISSN={0104-6632},  url={https://doi.org/10.1590/S0104-66322006000300005},  DOI={10.1590/S0104-66322006000300005},  number={3},  journal={Brazilian Journal of Chemical Engineering},  publisher={Brazilian Society of Chemical Engineering},  author={Perez, Y. G. and Leite, S. G .F. and Coelho, M. A. Z.},  year={2006},  month={Jul},  pages={319–330} }