1. “World Internet users and 2014 population stats,” Internet World Stats, accessed April 3, 2015, www.internetworldstats.com/stats.htm.
2. “comScore Media Metrix multi-Platform & Mobile Metrix, U.S., June 2013- June 2014,” accessed April 3, 2015, www.comscore. com/Products/Audience-Analytics/Media-Metrix-Multi-Platform.
3. Gonzalez, Marta C., Cesar A. Hidalgo, and Albert-Laszlo Barabasi. “Understanding individual human mobility patterns.” Nature 453. 7196 (2008): 779-782.
4. Song, Chaoming, Zehui Qu, Nicholas Blumm, and Albert-László Barabási. “Limits of predictability in human mobility.” Science 327, no. 5968 (2010): 1018-1021.
5. Miluzzo, Emiliano, Nicholas D. Lane, Kristóf Fodor, Ronald Peterson, Hong Lu, Mirco Musolesi, Shane B. Eisenman, Xiao Zheng, and Andrew T. Campbell. “Sensing meets mobile social networks: the design, implementation and evaluation of the cenceme application.” In Proceedings of the 6th ACM conference on Embedded network sensor systems, pp. 337-350.