@article{fama1993,
  title={Common risk factors in the returns on stocks and bonds},
  author={Eugene F. Fama and Kenneth R. French},
  year={1993},
  journal={Journal of Financial Economics},
  doi={10.1016/0304-405x(93)90023-5},
  url={https://doi.org/10.1016/0304-405x(93)90023-5}
}