To cite convoSPAT in publications use:

Risser MD, Calder CA (2017). “Local Likelihood Estimation for Covariance Functions with Spatially-Varying Parameters: The convoSPAT Package for R.” Journal of Statistical Software, 81(14), 1–32. doi:10.18637/jss.v081.i14.

Corresponding BibTeX entry:

  @Article{,
    title = {Local Likelihood Estimation for Covariance Functions with
      Spatially-Varying Parameters: The {convoSPAT} Package for {R}},
    author = {Mark D. Risser and Catherine A. Calder},
    journal = {Journal of Statistical Software},
    year = {2017},
    volume = {81},
    number = {14},
    pages = {1--32},
    doi = {10.18637/jss.v081.i14},
  }