1. Cavazza F. Social media landscape 2015. http://www.fredcavazza.net/2015/06/03/social-media-landscape-2015/. Accessed January 15, 2016.
2. Barthel M, Shearer E, Gottfried J, et al. The evolving role of news on Twitter and Facebook, July 2015. Pew Research Center website. http://www.journalism.org/2015/07/14/the-evolving-role-of-news-on-twitter-and-facebook/. Published July 14, 2015. Accessed February 15, 2016.
3. Wihbey J. The challenges of democratizing news and information: Examining data on social media, viral patterns and digital influence. Shorenstein Center On Media, Politics and Public Policy, Harvard Kennedy School. Discussion Paper Series #D-85, June 2014. http://shorensteincenter.org/wp-content/uploads/2014/06/d85-wihbey.pdf. Accessed February 15, 2016.
4. Brian S. Defining social media. http://www.briansolis.com/2007/06/defining-social-media/. Accessed January 15, 2016.
5. Fox S. The social life of health information. Pew Research Center website. http://www.pewresearch.org/fact-tank/2014/01/15/the-social-life-of-health-information/. Accessed January 20, 2016.