1. A method of generating answers to questions, comprising: receiving an input query; conducting a search in a data source to identify a candidate answer to the input query; identifying a proof of the candidate answer, said proof including a series of premises for establishing said proof; identifying documents that include references to said premises, each of said documents including one or more references to one or more of said premises; selecting a set of the documents that, as a set, include references to all of the premises; and using the selected set of documents to generate a score for the candidate answer.