13. The system of claim 12 , wherein identifying conceptually similar terms for each of the graph terms comprises: identifying a first set of conceptually similar terms for the first object concept; identifying a second set of conceptually similar terms for the second object concept; and identifying a third set of conceptually similar terms for the linking concept term.
13. The system of claim 12 , wherein identifying conceptually similar terms for each of the graph terms comprises: identifying a first set of conceptually similar terms for the first object concept; identifying a second set of conceptually similar terms for the second object concept; and identifying a third set of conceptually similar terms for the linking concept term. 15. The system of claim 13 , wherein the instructions further configure the processor to: modify corresponding mappings in the first knowledge base, for each respective term in the first set of conceptually similar terms, to include an indication that the respective term in the first set of conceptually similar terms is associated with a respective first object concept having unknown referent data; modify corresponding mappings, in the first knowledge base, for each respective term in the second set of conceptually similar terms to include an indication that the respective the term in the second set of conceptually similar terms is associated with a respective second object concept having unknown referent data; and modify corresponding mappings, in the first knowledge base, for each respective term in the third set of conceptually similar terms to include an indication that the respective term in the third set of conceptually similar terms is associated with a respective linking concept, wherein at least a portion of the modified mappings is used to identify the respective potential referent data.