1. P.R. Bureau, world population data sheet, 2016, PRBhttp://www.prb.org/Publications/Datasheets/2016/2016-world-population-data-sheet.aspx.
2. J. Mander, Internet users have average of 5.54 social media accounts, Global web index https://blog.globalwebindex.net/chart-of-the-day/internet-users-have-average-of-5-54-social-media-accounts/.
3. D. Bisson, Social engineering attacks to watch out for, Tripwire https://www.tripwire.com/state-of-security/security-awareness/5-social-engineering-attacks-to-watch-out-for/.
4. On Cybersecurity, Crowdsourcing, and Social Cyber-Attack;Goolsby,2013
5. Detecting and characterizing social spam campaigns;Gao,2010