1. Apache HBase -- a Distributed Hadoop Database. https://hbase.apache.org/. Apache HBase -- a Distributed Hadoop Database. https://hbase.apache.org/.
2. Java Array Copy. https://docs.oracle.com/javase/7/docs/api/java/lang/System.html . Java Array Copy. https://docs.oracle.com/javase/7/docs/api/java/lang/System.html .
3. Java Concurrent Skip List. https://docs.oracle.com/javase/7/docs/api/java/util/concurrent/ConcurrentSkipListMap.html . Java Concurrent Skip List. https://docs.oracle.com/javase/7/docs/api/java/util/concurrent/ConcurrentSkipListMap.html .
4. http://flurrymobile.tumblr.com/post/144245637325/appmatrix. http://flurrymobile.tumblr.com/post/144245637325/appmatrix.
5. Flurry analytics. https://developer.yahoo.com/flurry/docs/analytics/. Flurry analytics. https://developer.yahoo.com/flurry/docs/analytics/.