The Enterprise Knowledge Graph Foundation has published a set of principles for an Enterprise Knowledge Graph (EKG).
A knowledge graph is one approach to storing information within a knowledge base. The article, What is a Knowledge Graph? is an explanation of what a knowledge graph is (and isn't) and the difference between a knowledge base and a database. You can download the knowledge base GraphDB here. This is a quick start guide for GraphDB. Or, you can fiddle around in the Neo4j Sandbox here.
This is an excellent article that explains why graph databases are the future of databases. This is excellent information aboug GSQL which is a graph query language.
Ontology + Data = Knowledge Graph
A Brief History of Knowledge Graph's Main Ideas: A Tutorial
Introduction to Knowledge the Graph
Creating a small knowlege graph video series: