@article{obeng_2021,  title={Apoptosis (programmed cell death) and its signals - A review},  volume={81},  ISSN={1519-6984},  url={https://doi.org/10.1590/1519-6984.228437},  DOI={10.1590/1519-6984.228437},  number={4},  journal={Brazilian Journal of Biology},  publisher={Instituto Internacional de Ecologia},  author={Obeng, E.},  year={2021},  month={Oct},  pages={1133–1143} }