@article{salazar-valencia_pérez-merchancano_bolívar-marinéz_2006,  title={Optical properties in Biopolymers: lignin fragmen},  volume={36},  ISSN={0103-9733},  url={https://doi.org/10.1590/S0103-97332006000600011},  DOI={10.1590/S0103-97332006000600011},  number={3b},  journal={Brazilian Journal of Physics},  publisher={Sociedade Brasileira de Física},  author={Salazar-Valencia, P. J. and Pérez-Merchancano, S. T. and Bolívar-Marinéz, L. E.},  year={2006},  month={Sep},  pages={840–843} }