To cite classify in publications use:

Christopher Wheadon (2014). Classification Accuracy and Consistency under Item Response Theory Models Using the Package classify. Journal of Statistical Software, 56(10), 1-14. URL http://www.jstatsoft.org/v56/i10/.

Corresponding BibTeX entry:

  @Article{,
    title = {Classification Accuracy and Consistency under Item
      Response Theory Models Using the Package {classify}},
    author = {Christopher Wheadon},
    journal = {Journal of Statistical Software},
    year = {2014},
    volume = {56},
    number = {10},
    pages = {1--14},
    url = {http://www.jstatsoft.org/v56/i10/},
  }