@misc{W1951724000,
  author = {Douglas M. Bates and Martin Mächler and Benjamin M. Bolker and Steve Walker},
  title = {Fitting Linear Mixed-Effects Models Using lme4},
  year = {2015},
  howpublished = {Journal of Statistical Software},
  doi = {https://doi.org/10.18637/jss.v067.i01}
}