To cite ionr in publications use:

Vainik, U., Mottus, R., Allik, J., Esko, T., and Realo, A. Are Trait-Outcome Associations Caused by Scales or Particular Items? Example Analysis of Personality Facets and BMI. European Journal of Personality, 29(6), 688-634. URL http://onlinelibrary.wiley.com/doi/10.1002/per.2009/abstract.

Corresponding BibTeX entry:

  @Article{,
    title = {Are Trait-Outcome Associations Caused by Scales or
      Particular Items? Example Analysis of Personality Facets and
      BMI},
    author = {Uku Vainik and Rene Mottus and Juri Allik and Tonu Esko
      and Anu Realo},
    journal = {European Journal of Personality},
    year = {2015},
    volume = {29},
    number = {6},
    pages = {688--634},
    url =
      {http://onlinelibrary.wiley.com/doi/10.1002/per.2009/abstract},
  }