RDF/OWL blank node 空白节点

http://etutorials.org/Misc/Practical+resource+description+framework+rdf/Chapter+3.+The+Basic+Elements+Within+the+RDF+XML+Syntax/3.2+RDF+Blank+Nodes/ 

https://stackoverflow.com/questions/20071983/blank-node-in-rdf

https://stackoverflow.com/questions/6667655/how-to-distinguish-between-two-blank-nodes-in-rdf?rq=1

http://www.jsoftware.us/vol7/jsw0709-09.pdf

https://www.w3.org/TR/swbp-n-aryRelations/

https://www.w3.org/wiki/BlankNodes

https://en.wikipedia.org/wiki/Blank_node

https://community.neo4j.com/t/blank-nodes-in-rdf/10927