1. Dbpedia - a crystallization point for the web of data;Bizer;J. Web Semant.,2009
2. Freebase: A collaboratively created graph database for structuring human knowledge;Bollacker,2008
3. Yago3: A knowledge base from multilingual wikipedias;Mahdisoltani,2013
4. Wordnet: A lexical database for english;Miller;Commun. ACM,1995
5. Towards a definition of knowledge graphs;Ehrlinger,2016