To cite lightr in publications use:

  Gruson H, White T, Maia R (2019). “lightr: import spectral data and
  metadata in R.” _Journal of Open Source Software_, *4*(43), 1857.
  doi:10.21105/joss.01857 <https://doi.org/10.21105/joss.01857>,
  <https://doi.org/10.21105/joss.01857>.

A BibTeX entry for LaTeX users is

  @Article{,
    doi = {10.21105/joss.01857},
    url = {https://doi.org/10.21105/joss.01857},
    year = {2019},
    publisher = {The Open Journal},
    volume = {4},
    number = {43},
    pages = {1857},
    author = {Hugo Gruson and Thomas White and Rafael Maia},
    title = {lightr: import spectral data and metadata in R},
    journal = {Journal of Open Source Software},
  }