To cite GWmodel in publications use:

Isabella Gollini, Binbin Lu, Martin Charlton, Christopher Brunsdon, Paul Harris (2015). GWmodel: An R Package for Exploring Spatial Heterogeneity Using Geographically Weighted Models. Journal of Statistical Software, 63(17), 1-50. URL http://www.jstatsoft.org/v63/i17/.

Binbin Lu, Paul Harris, Martin Charlton, Christopher Brunsdon (2014). The GWmodel R package: further topics for exploring spatial heterogeneity using geographically weighted models. Geo-spatial Information Science, 17(2), 85-101. URL https://www.tandfonline.com/doi/abs/10.1080/10095020.2014.917453

Corresponding BibTeX entries:

  @Article{,
    title = {{GWmodel}: An {R} Package for Exploring Spatial
      Heterogeneity Using Geographically Weighted Models},
    author = {Isabella Gollini and Binbin Lu and Martin Charlton and
      Christopher Brunsdon and Paul Harris},
    journal = {Journal of Statistical Software},
    year = {2015},
    volume = {63},
    number = {17},
    pages = {1--50},
    url = {http://www.jstatsoft.org/v63/i17/},
  }
  @Article{,
    title = {The {GWmodel} {R} package: further topics for exploring
      spatial heterogeneity using geographically weighted models},
    author = {Binbin Lu and Paul Harris and Martin Charlton and
      Christopher Brunsdon},
    journal = {Geo-spatial Information Science},
    year = {2014},
    volume = {17},
    number = {2},
    pages = {85--101},
    url =
      {https://www.tandfonline.com/doi/abs/10.1080/10095020.2014.917453},
  }