@article{preacher2008,
  title={Asymptotic and resampling strategies for assessing and comparing indirect effects in multiple mediator models},
  author={Kristopher J. Preacher and Andrew F. Hayes},
  year={2008},
  journal={Behavior Research Methods},
  doi={10.3758/brm.40.3.879},
  url={https://doi.org/10.3758/brm.40.3.879}
}