To cite the nanop package in publications use:

Gagin, A., Mullen, K.M. & Levin, I. (2014), nanop: Tools for Nanoparticle Simulation and Calculation of PDF and Total Scattering Structure Function (R package), http://cran.r-project.org/web/packages/nanop

Gagin, A. and Levin, I. (2014) Combined fitting of small- and wide-angle X-ray total scattering data from nanoparticles: benefits and issues J. Appl. Cryst. 47:619--629

As nanop is continually evolving, you may want to cite its version number. Find it with 'help(package=nanop)'.

Corresponding BibTeX entries:

  @Manual{,
    title = {nanop: Tools for Nanoparticle Simulation and Calculation
      of PDF and Total Scattering Structure Function},
    author = {Anton Gagin and Katharine Mullen and Igor Levin},
    year = {2014},
    note = {R package version 2.0-4},
    url = {http://CRAN.R-project.org/package=nanop},
  }
  @Article{,
    author = {Anton Gagin and Igor Levin},
    title = {Combined fitting of small- and wide-angle X-ray total
      scattering data from nanoparticles: benefits and issues},
    journal = {Journal of Applied Crystallography},
    year = {2014},
    volume = {47},
    pages = {619--629},
    url = {http://journals.iucr.org/j/issues/2014/02/00/to5066/},
  }