1. Linked data-the story so far;Bizer;Semant. Serv. Interoperability Web Appl,2009
2. Freebase: a collaboratively created graph database for structuring human knowledge;Bollacker,2008
3. Dbpedia: A Nucleus for a Web of Open Data;Auer,2007
4. Yago2: a spatially and temporally enhanced knowledge base from wikipedia;Hoffart,2013
5. Grounded unsupervised semantic parsing.;Poon,2013