To cite package 'qualV' in publications use:

  Jachner, S., K. G. van den Boogaart and T. Petzoldt (2007).
  Statistical Methods for the Qualitative Assessment of Dynamic Models
  with Time Delay (R Package qualV). Journal of Statistical Software,
  22(8), 1--30. doi:10.18637/jss.v022.i08

A BibTeX entry for LaTeX users is

  @Article{,
    title = {Statistical Methods for the Qualitative Assessment 
    of Dynamic Models with Time Delay (R Package qualV)},
    author = {{Stefanie  Jachner} and {K. Gerald van den Boogaart} and {Thomas  Petzoldt}},
    journal = {Journal of Statistical Software},
    volume = {22},
    number = {8},
    pages = {1--30},
    year = {2007},
    doi = {10.18637/jss.v022.i08},
    keywords = {ecological modeling, qualitative validation criteria, time shift, R.},
  }