@article{us_ugur_2021,  title={Has external banding become a historical technique during venous valve repair?},  volume={67},  ISSN={0104-4230},  url={https://doi.org/10.1590/1806-9282.20210721},  DOI={10.1590/1806-9282.20210721},  number={11},  journal={Revista da Associação Médica Brasileira},  publisher={Associação Médica Brasileira},  author={Us, Melih Hulusi and Ugur, Murat},  year={2021},  month={Nov},  pages={1676–1680} }