The references are listed here:
https://github.com/apache/spark/tree/master/examples/src/main/scala/org/apache/spark/examples
Google Dremel paper at http://research.google.com/pubs/pub36632.html
https://blog.twitter.com/2013/dremel-made-simple-with-parquet
http://planetcassandra.org/getting-started-with-apache-spark-and-cassandra/
http://blog.cloudera.com/blog/2014/12/new-in-cloudera-labs-sparkonhbase/