To cite gRc in publications use:

Søren Højsgaard, Steffen Lauritzen (2007). Inference in Graphical Gaussian Models with Edge and Vertex Symmetries with the gRc Package for R. Journal of Statistical Software, 23(6), 1-26. URL http://www.jstatsoft.org/v23/i06/

Søren Højsgaard, Steffen Lauritzen (2008). Graphical Gaussian models with edge and vertex symmetries. Journal of the Royal Statistical Society, Series~B, 70(5), 1005-1027 URL https://rss.onlinelibrary.wiley.com/doi/10.1111/j.1467-9868.2008.00666.x

Corresponding BibTeX entries:

  @Article{,
    title = {Inference in Graphical {G}aussian Models with Edge and
      Vertex Symmetries with the {gRc} Package for {R}},
    author = {S{\o}ren H{\o}jsgaard and Steffen Lauritzen},
    journal = {Journal of Statistical Software},
    year = {2007},
    volume = {23},
    number = {6},
    pages = {1--26},
    doi = {10.18637/jss.v023.i06},
    url = {http://www.jstatsoft.org/v23/i06/},
  }

  @Article{,
    title = {Graphical {G}aussian models with edge and vertex
      symmetries},
    author = {S{\o}ren H{\o}jsgaard and Steffen Lauritzen},
    journal = {Journal of the Royal Statistical Society, Series~B},
    year = {2008},
    volume = {70},
    number = {5},
    pages = {1005--1027},
    doi = {10.1111/j.1467-9868.2008.00666.x},
    url =
      {https://rss.onlinelibrary.wiley.com/doi/10.1111/j.1467-9868.2008.00666.x},
  }