To cite glottospace in publications use:

  Norder, S.J. et al. (2022). glottospace: R package for the geospatial
  analysis of linguistic and cultural data. URL
  https://github.com/SietzeN/glottospace.

A BibTeX entry for LaTeX users is

  @Unpublished{,
    title = {glottospace: R package for the geospatial analysis of linguistic and cultural data},
    author = {Sietze Norder},
    note = {Manuscript under preparation},
    url = {https://github.com/SietzeN/glottospace},
  }