The following references can be used to cite this two-tailed area under the standard normal distribution calculator:

| Soper, D.S. (2015). Two-Tailed Area Under the Standard Normal Distribution Calculator [Software]. Available from http://www.danielsoper.com/statcalc |

| Abramowitz, M. and Stegun, I.A., eds. (1965). Handbook of Mathematical Functions. New York, NY: Dover. |