1. http://docs.oracle.com/cd/E37231_01/doc.20/e36961/sqlch.htm
(2013)
2. Citusdata (2013).
http://citusdata.com/docs/SQL-on-Hadoop
3. Cloudera impala (2013).
http://blog.cloudera.com/blog/2012/10/cloudera-impala-real-time-queries-in-apache-hadoop-for-real/
4. Drill proposal (2013).
http://wiki.apache.org/incubator/DrillProposal/
5. Jethro data (2013).
http://jethrodata.com/product/