To cite Bergm in publications use:

Alberto Caimo, Nial Friel (2014). Bergm: Bayesian Exponential Random Graphs in R. Journal of Statistical Software, 61(2), 1-25. URL http://www.jstatsoft.org/v61/i02/.

Corresponding BibTeX entry:

  @Article{,
    title = {{Bergm}: {B}ayesian Exponential Random Graphs in {R}},
    author = {Alberto Caimo and Nial Friel},
    journal = {Journal of Statistical Software},
    year = {2014},
    volume = {61},
    number = {2},
    pages = {1--25},
    url = {http://www.jstatsoft.org/v61/i02/},
  }