1. Mell, P, Grance, T.: Draft nist working definition of cloud com-puting. Referenced on Jan. 23rd (2010)
2. Cloud Security Alliance : Security Guidance for Critical Areas of Focus in Cloud Computing.
http://www.cloudsecurityalliance.org
(2009)
3. Slocum, Z.: Your Google Docs: Soon in Search Results?’
http://news.cnet.com/8301-17939_109-10357137-2.html
(2009)
4. Zerr, S, Olmedilla, D, Nejdl, W, Siberski, W.: Zerber+ r: top-k retrieval from a confidential index. In: International Conference on Extending Database Technology: Advances in Database Technology pp. 439–449, ACM (2009)
5. Masram, R., Shahare, V.: Analysis and comparison of symmetric key cryptographic algorithms based on various file feature. Int. J. Netw. Secur. Appl 6(4), 43 (2014)