To cite package gstat in publications use:

Pebesma EJ (2004). “Multivariable geostatistics in S: the gstat package.” Computers & Geosciences, 30, 683-691. https://doi.org/10.1016/j.cageo.2004.03.012.

Gräler B, Pebesma E, Heuvelink G (2016). “Spatio-Temporal Interpolation using gstat.” The R Journal, 8, 204-218. https://journal.r-project.org/archive/2016/RJ-2016-014/index.html.

Corresponding BibTeX entries:

  @Article{,
    title = {Multivariable geostatistics in {S}: the gstat package},
    author = {Edzer J. Pebesma},
    journal = {Computers & Geosciences},
    year = {2004},
    volume = {30},
    pages = {683-691},
    url = {https://doi.org/10.1016/j.cageo.2004.03.012},
  }

  @Article{,
    title = {Spatio-Temporal Interpolation using gstat},
    author = {Benedikt Gräler and Edzer Pebesma and Gerard Heuvelink},
    year = {2016},
    journal = {The R Journal},
    volume = {8},
    issue = {1},
    pages = {204-218},
    url =
      {https://journal.r-project.org/archive/2016/RJ-2016-014/index.html},
  }