1. http://en.wikipedia.org/wiki/Caesar_Code . Accessed 4 July 2013.
2. http://memory.loc.gov/ammem/nfhtml/nfhome.html . Accessed 21 June 2013.
3. http://mase.itc.nagoya-u.ac.jp/CARPE2006/ . Accessed 21 June 2013.
4. Bush. V. (1945). As we may think. The Atlantic, July 1945. http://www.theatlantic.com/magazine/archive/1945/07/as-we-may-think/303881/ . Accessed 21 June 2013.
5. Gemmell, J., Williams, L., Wood, K., Lueder, R., & Bell, G. (2004). Passive capture and ensuing issues for a personal lifetime store. Proceedings of the First ACM workshop on continuous archival and retrieval of personal experiences (pp. 48–55). New York: ACM,