To cite pcse in publications use:

Delia Bailey, Jonathan N. Katz (2011). Implementing Panel-Corrected Standard Errors in R: The pcse Package. Journal of Statistical Software, Code Snippets, 42(1), 1-11. URL http://www.jstatsoft.org/v42/c01/.

Corresponding BibTeX entry:

  @Article{,
    title = {Implementing Panel-Corrected Standard Errors in {R}: The
      {pcse} Package},
    author = {Delia Bailey and Jonathan N. Katz},
    journal = {Journal of Statistical Software, Code Snippets},
    year = {2011},
    volume = {42},
    number = {1},
    pages = {1--11},
    url = {http://www.jstatsoft.org/v42/c01/},
  }