@article{sousa_2011,  title={A Levenberg-Marquardt algorithm for fi tting σ-w curves from three-point bend tests for plain and fi ber reinforced concretes},  volume={4},  ISSN={1983-4195},  url={https://doi.org/10.1590/S1983-41952011000400010},  DOI={10.1590/S1983-41952011000400010},  number={4},  journal={Revista IBRACON de Estruturas e Materiais},  publisher={IBRACON - Instituto Brasileiro do Concreto},  author={Sousa, J.L.A.O.},  year={2011},  month={Oct},  pages={691–694} }