To cite package pavo in publications use:

Maia R., Gruson H., Endler J. A., White T. E. 2019. pavo 2: new tools for the spectral and spatial analysis of colour in R. Methods in Ecology and Evolution.

Corresponding BibTeX entry:

  @Article{,
    title = {pavo 2: 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 = {Methods in Ecology and Evolution},
    year = {2019},
  }