1. Amazon S3 Pricing. http://aws.amazon.com/s3/pricing/. Amazon S3 Pricing. http://aws.amazon.com/s3/pricing/.
2. Bitcoin real-time stats and tools. http://blockexplorer.com/q. Bitcoin real-time stats and tools. http://blockexplorer.com/q.
3. Google Cloud Storage. https://cloud.google.com/storage/. Google Cloud Storage. https://cloud.google.com/storage/.
4. The MySQL Query Cache. http://dev.mysql.com/doc/refman/5.1/en/query-cache.html. The MySQL Query Cache. http://dev.mysql.com/doc/refman/5.1/en/query-cache.html.