https://www.washingtonpost.com/news/morning-mix/wp/2015/02/02/using-an-ipad-or-smartphone-can-harm-a-toddlers-brain-researchers-says/

http://www.interactivekidsllc.com/importance-of-social-skills/

http://www.wsj.com/articles/SB10001424052702304363104577391813961853988