To cite the psyosphere package in publications use:

Ziepert B, Ufkes E, de Vries P (2020). psyosphere: Analyse GPS Data. University of Twente, Enschede, Netherlands. R package version 0.1.5, https://CRAN.R-project.org/package=psyosphere.

Corresponding BibTeX entry:

  @Manual{,
    title = {psyosphere: Analyse GPS Data},
    author = {Benjamin Ziepert and Elze G Ufkes and Peter W {de
      Vries}},
    organization = {University of Twente},
    address = {Enschede, Netherlands},
    year = {2020},
    note = {R package version 0.1.5},
    url = {https://CRAN.R-project.org/package=psyosphere},
  }