Please cite both the package and the original articles / software in your publications:

Mouselimis L (2021). CopernicusDEM: Copernicus Digital Elevation Models. R package version 1.0.1 produced using Copernicus WorldDEMTM-90 DLR e.V. 2010-2014 and Airbus Defence and Space GmbH 2014-2018 provided under COPERNICUS by the European Union and ESA; all rights reserved, https://CRAN.R-project.org/package=CopernicusDEM.

Corresponding BibTeX entry:

  @Manual{,
    title = {{CopernicusDEM}: Copernicus Digital Elevation Models},
    author = {Lampros Mouselimis},
    year = {2021},
    note = {R package version 1.0.1 produced using Copernicus
      WorldDEMTM-90 DLR e.V. 2010-2014 and Airbus Defence and Space
      GmbH 2014-2018 provided under COPERNICUS by the European Union
      and ESA; all rights reserved},
    url = {https://CRAN.R-project.org/package=CopernicusDEM},
  }