To cite the loo R package and/or paper in publications use:

Aki Vehtari, Andrew Gelman, and Jonah Gabry. (2016). loo: Efficient leave-one-out cross-validation and WAIC for Bayesian models. R package version 1.0.0. https://github.com/stan-dev/loo

Aki Vehtari, Andrew Gelman, and Jonah Gabry. (2016). Practical Bayesian model evaluation using leave-one-out cross-validation and WAIC. Statistics and Computing.<doi:10.1007/s11222-016-9696-4>

Corresponding BibTeX entries:

  @Manual{,
    title = {loo: Efficient leave-one-out cross-validation and WAIC for
      Bayesian models},
    author = {Aki Vehtari and Andrew Gelman and Jonah Gabry},
    year = {2016},
    note = {R package version 1.0.0},
    url = {https://github.com/stan-dev/loo},
  }
  @Article{,
    title = {Practical Bayesian model evaluation using leave-one-out
      cross-validation and WAIC},
    author = {Aki Vehtari and Andrew Gelman and Jonah Gabry},
    year = {2016},
    journal = {Statistics and Computing},
  }