To cite A3 in publications use:

  Scott Fortmann-Roe (2015). Consistent and Clear Reporting of Results
  from Diverse Modeling Techniques: The A3 Method. Journal of
  Statistical Software, 66(7), 1-23. URL
  http://www.jstatsoft.org/v66/i07/.

A BibTeX entry for LaTeX users is

  @Article{,
    title = {Consistent and Clear Reporting of Results from Diverse Modeling Techniques: The A3 Method},
    author = {Scott Fortmann-Roe},
    journal = {Journal of Statistical Software},
    year = {2015},
    volume = {66},
    number = {7},
    pages = {1--23},
    url = {http://www.jstatsoft.org/v66/i07/},
  }