@article{chaudhuri_2001,  title={Positronium formation from hydrogen negative Ion, H<FONT FACE=Symbol>-</FONT>},  volume={31},  ISSN={0103-9733},  url={https://doi.org/10.1590/S0103-97332001000100001},  DOI={10.1590/S0103-97332001000100001},  number={1},  journal={Brazilian Journal of Physics},  publisher={Sociedade Brasileira de Física},  author={Chaudhuri, Puspitapallab},  year={2001},  month={Mar},  pages={1–7} }