To cite package ‘etn’ in publications use:

  Huybrechts P, Desmet P, Oldoni D, Van Hoey S (2024). _etn: Access
  Data from the European Tracking Network_. R package version 2.2.1,
  <https://inbo.github.io/etn/>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {etn: Access Data from the European Tracking Network},
    author = {Pieter Huybrechts and Peter Desmet and Damiano Oldoni and Stijn {Van Hoey}},
    year = {2024},
    note = {R package version 2.2.1},
    url = {https://inbo.github.io/etn/},
  }