@article{kroenke2001,
  title={The PHQ-9},
  author={Kurt Kroenke and Robert L. Spitzer and Janet B. W. Williams},
  year={2001},
  journal={Journal of General Internal Medicine},
  doi={10.1046/j.1525-1497.2001.016009606.x},
  url={https://doi.org/10.1046/j.1525-1497.2001.016009606.x}
}