1. Apache Hadoop. http://hadoop.apache.org (12/24/15).
2. Apache Hadoop 2.7.1. MapReduce Tutorial. Reducer: How Many Reduces? http://hadoop.apache.org/docs/current/hadoop-mapreduce-client/hadoop-mapreduce-client-core/MapReduceTutorial.html#Reducer (09/09/2015).
3. Hadoop Wiki: HowManyMapsAndReduces. http://wiki.apache.org/hadoop/HowManyMapsAndReduces (09/09/2015).
4. Apache Spark. http://spark.apache.org (12/24/15).
5. Apache Spark Dynamic Resource Allocation. http://spark.apache.org/docs/latest/job-scheduling.html#dynamic-resource-allocation (12/24/15).