1. What is brain wave [online] http://www.brainworksneurotherapy.com/what-are-brainwaves.
2. Brain wave [online] http://www.transparentcorp.com/products/np/brainwaves.php.
3. Type of wave [Online] http://mentalhealthdaily.com/2014/04/15/5-types-of-brain-waves-frequencies-gamma-beta-alpha-theta-delta/.
4. Gama wave [Online] http://mentalhealthdaily.com/2014/03/12/gamma-brain-waves-40-hz-to-100-hz/.
5. Beta wave [Online] http://mentalhealthdaily.com/2014/04/10/beta-brain-waves-12-hz-to-40-hz/.