To cite ecmwfr in publications use:

Hufkens, Stauffer and Campitelli (2019). The ecwmfr package: an interface to ECMWF API endpoints https://doi.org/10.5281/zenodo.2647541

Corresponding BibTeX entry:

  @Misc{,
    title = {The ecwmfr package: an interface to ECMWF API endpoints},
    author = {Koen Hufkens and Reto Stauffer and Elio Campitelli},
    year = {2019},
    doi = {10.5281/zenodo.2647541},
    url = {https://khufkens.github.io/ecmwfr/},
  }