1. http://www.vcloudnews.com/every-day-big-data-statistics-2-5-quintillion-bytes-of-data-created-daily/
2. http://www.osp.ru/os/2013/08/13037856
3. https://ru.wikipedia.org/wiki/Hadoop
4. Ryabov, S., & Korshunov, A. (2011). The distributed algorithm for finding communities of users in social networks. – 2011. p. 215.
5. https://dev.twitter.com/overview/documentation