Neo4j

"Neo4j enables organizations to unlock the business value of connections, influences and relationships in data: through new applications that adapt to changing business needs, and by enabling existing applications to scale with the business. Headquartered in San Mateo, USA, Neo4j has offices in Sweden, the UK and Germany." to find out more...

"Neo4j is committed to open source. Neo4j Community Edition is fully open source, licensed and distributed under GPL v3.

Neo4j offers a number of commercial licensing options, outlined above: both paid and free, including free licenses for development, startup, and academic-educational uses and of course evaluation.

Neo4j Enterprise Edition is available for download as a zipfile/tarball as well as via Debian, RPM, DockerHub, and more; as well as via under a "bring your own license" model in Cloud services, including Google Compute Platform, Microsoft Azure, and Amazon EC2.

Visit the Neo4j Open Source Project page to learn more about the history behind Neo4j." to find more...

Passage via:

• https://neo4j.com/company/
• https://neo4j.com/licensing/#:~:text=Neo4j%20is%20committed%20to%20open,uses%20and%20of%20course%20evaluation.

Related links: 

• https://www.youtube.com/neo4j
• https://neo4j.com/webinars/
• https://neo4j.com/graphacademy/online-training/
• https://youtu.be/xcWysEpxz1Q (Will Reynolds - Modelling HVAC & MEP services Neo4j)
• https://www.autodesk.com/autodesk-university/class/Representing-MEP-Systems-Graph-Data-Rapid-Simulation-and-Analysis-2018#video (Will Reynolds - Autodesk Revit MEP API)
• https://github.com/ifcwebserver
• https://www.slideshare.net/neo4j/neanex-semantic-construction-with-graphs-91674084

Learning Cypher (Graph Query Language):

• https://youtu.be/l76udM3wB4U (20mins video by Ryan Boyd)
• https://www.w3.org/wiki/Cypher 
• https://en.wikipedia.org/wiki/Cypher_(query_language)

Graph Algorithm & Graph Database

• https://neo4j.com/graph-algorithms-book/?ref=home (Graph Algorithms)
• https://neo4j.com/graph-databases-book/?ref=home (Graph Database)