@article{souza_sales_2004,  title={O gênero Staelia Cham. & Schltdl. (Rubiaceae - Spermacoceae) no Estado de Pernambuco, Brasil},  volume={18},  ISSN={0102-3306},  url={https://doi.org/10.1590/S0102-33062004000400023},  DOI={10.1590/S0102-33062004000400023},  number={4},  journal={Acta Botanica Brasilica},  publisher={Sociedade Botânica do Brasil},  author={Souza, Elnatan Bezerra de and Sales, Margareth Ferreira de},  year={2004},  month={Oct},  pages={919–926} }