To cite metafor in publications use:

Wolfgang Viechtbauer (2010). Conducting meta-analyses in R with the metafor package. Journal of Statistical Software, 36(3), 1-48. URL http://www.jstatsoft.org/v36/i03/.

Corresponding BibTeX entry:

  @Article{,
    title = {Conducting meta-analyses in {R} with the {metafor}
      package},
    author = {Wolfgang Viechtbauer},
    journal = {Journal of Statistical Software},
    year = {2010},
    volume = {36},
    number = {3},
    pages = {1--48},
    url = {http://www.jstatsoft.org/v36/i03/},
  }