IBM Graph
The Best Bet: Graph Recommendation Engines - Bluemix Blog
https://developer.ibm.com/bluemix/2016/05/09/graph-recommendation-engines/
IBM Graph - IBM Cloud Data Services- IBM Analytics
http://www.ibm.com/analytics/us/en/technology/cloud-data-services/graph/
IBM Graph - Overview
https://ibm-graph-docs.ng.bluemix.net/index.html
Apache TinkerPop