1. A computer-implemented method for linking documents that refer to other documents through implicit linkages, the method comprising: identifying a first document, the first document comprising an authoritative comment regarding a second document; establishing an explicit linkage between the first document and the second document based upon the authoritative comment; identifying one or more third documents based upon the existence of a citation relationship between the second document and each of the one or more third documents detecting an implicit relationship between the first document and the one or more third documents by using common information between the second document and the one or more third documents; generating an impact value for each of the one or more third documents by comparing the implicit relationship with the first document to the explicit relationship with the second document, the impact value being an indicator of the implicit relationship between the first document and each of the one or more third documents; linking the first document to the one or more third documents based upon the impact value; and presenting the one or more third documents in response to a query for the first document.
9. The computer-implemented method of claim 1 , further comprising: including in the linkage additional documents citing or being cited by the one or more third documents.