To cite package pavo (>2.0) in publications use:

Maia R., Gruson H., Endler J. A., White T. E. 2018. pavo 2.0: new tools for the spectral and spatial analysis of colour in R. bioRxiv.

Corresponding BibTeX entry:

  @Article{,
    title = {pavo 2.0: new tools for the spectral and spatial analysis
      of colour in R},
    author = {Rafael Maia and Hugo Gruson and John A. Endler and Thomas
      E. White},
    journal = {bioRxiv},
    year = {2018},
  }