To cite popbio in publications use:

Stubben, C.J. and Milligan, B.G. 2007. Estimating and Analyzing Demographic Models Using the popbio Package in R. Journal of Statistical Software 22:11.

The paper is available at http://www.jstatsoft.org/v22/i11

Corresponding BibTeX entry:

  @Article{,
    author = {Chris J. Stubben and Brook G. Milligan},
    title = {Estimating and Analyzing Demographic Models Using the
      popbio Package in R},
    journal = {Journal of Statistical Software},
    volume = {22},
    number = {11},
    year = {2007},
  }