To cite package ‘swephR’ in publications use:

  Reijs V, Stubner R (2020). “Swiss Ephemeris: An Accurate Ephemeris
  Toolset for Astronomy and Astrology.” _Journal of Skyscape
  Archaeology_, *6*(1), 150-154. doi:10.1558/jsa.42323
  <https://doi.org/10.1558/jsa.42323>.

A BibTeX entry for LaTeX users is

  @Article{,
    title = {Swiss Ephemeris: An Accurate Ephemeris Toolset for Astronomy and Astrology},
    author = {Victor Reijs and Ralf Stubner},
    journal = {Journal of Skyscape Archaeology},
    year = {2020},
    volume = {6},
    number = {1},
    pages = {150--154},
    doi = {10.1558/jsa.42323},
    month = {Sep.},
  }