18. The system of claim 12 , the co-citation graph further comprises an edge that couples the first node and the second node, wherein length of the edge is indicative of a number of times that the first research document and the second research document are co-cited by other research documents.
12. A system comprising: a processor; and a memory that comprises components that are executable by the processor, the components comprising: a receiver component that is configured to receive a request for a co-citation graph for a first research document, the first research document has an author and includes citations to other research documents; and a co-citation graph generator component that is configured to: execute a search over contents of a data repository responsive to receiving the request, the data repository comprises a plurality of research documents including the first research document; and based upon the search, generate a co-citation graph for the first research document for presentment on a display, the co-citation graph comprises: a first node that is representative of the first research document; a second node that is representative of a second research document; a plurality of nodes that are respectively representative of a plurality of other research documents, each research document in the plurality of other research documents comprising sentences that include citations to the first research document and the second research document; and graphical data that indicates that each research document in the plurality of other research documents comprises the sentences that include the citations to the first research document and the second research document.