To cite package queueing in publications use:

  R original by Pedro Canadilla (2009). queueing: Markovian Queueing systems. R package
  version 0.1.0.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {queueing: Markovian Queueing systems},
    author = {R original by Pedro Canadilla},
    year = {2010},
    note = {R package version 0.1.0},
  }
