To cite validann in publications use:

Humphrey, G.B., Maier, H.R., Wu, W., Mount, N.J., Dandy, G.C., Abrahart, R.J., Dawson, C.W. (2017). Improved validation framework and R-package for artificial neural network models. Environmental Modelling & Software, 92, 82-106. URL http://doi.org/10.1016/j.envsoft.2017.01.023.

Corresponding BibTeX entry:

  @Article{,
    title = {Improved validation framework and R-package for artificial
      neural network models},
    author = {{Humphrey} and {G.B.} and {Maier} and {H.R.} and {Wu} and
      {W.} and {Mount} and {N.J.} and {Dandy} and {G.C.} and {Abrahart}
      and {R.J.} and {Dawson} and {C.W.}},
    journal = {Environmental Modelling & Software},
    year = {2017},
    volume = {92},
    pages = {82--106},
    url = {http://doi.org/10.1016/j.envsoft.2017.01.023},
  }