@article{berg_1977,  title={Gecropia purpurascens, a new species for Brazilian Amazonia},  volume={7},  ISSN={0044-5967},  url={https://doi.org/10.1590/1809-43921977072185},  DOI={10.1590/1809-43921977072185},  number={2},  journal={Acta Amazonica},  publisher={Instituto Nacional de Pesquisas da Amazônia},  author={Berg, C. C.},  year={1977},  month={Jun},  pages={185–188} }