To cite abctools in publications use:

Matthew A Nunes, Dennis Prangle (2015). abctools: An R package for tuning Approximate Bayesian Computation analyses. Forthcoming.

Corresponding BibTeX entry:

  @Unpublished{,
    title = {abctools: An {R} package for tuning {Approximate Bayesian
      Computation} analyses},
    author = {Matthew A. Nunes and Dennis Prangle},
    year = {2015},
    note = {Forthcoming},
  }