To cite SNSequate in publications use:

Gonz├ílez J (2014). “SNSequate: Standard and Nonstandard Statistical Models and Methods for Test Equating.” Journal of Statistical Software, 59(7), 1–30. http://www.jstatsoft.org/v59/i07/.

Corresponding BibTeX entry:

  @Article{,
    title = {{SNSequate}: Standard and Nonstandard Statistical Models
      and Methods for Test Equating},
    author = {Jorge Gonz{\'a}lez},
    journal = {Journal of Statistical Software},
    year = {2014},
    volume = {59},
    number = {7},
    pages = {1--30},
    url = {http://www.jstatsoft.org/v59/i07/},
  }