Primary text examples.

http://www.dailymail.co.uk/sciencetech/article-2066803/Violent-video-games-DO-make-people-aggressive.html

http://www.dailymail.co.uk/sciencetech/article-2067607/Violent-games-DO-alter-brain--effect-visible-MRI-scans-just-week.html

http://www.dailymail.co.uk/news/article-1390672/Fury-Call-Duty-game-recreates-7-7-Tube-bomb-attacks.html

http://www.medicalnewstoday.com/releases/191171.php

http://www.dana.org/news/cerebrum/detail.aspx?id=22800