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/.

Corresponding BibTeX entry:

  @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},
    url = {http://www.jstatsoft.org/v23/i06/},
  }