US 6285999, Page, Lawrence, "Method for node ranking in a linked database", published 1998-01-09, issued 2001-09-04. "A method assigns importance ranks to nodes in a linked database, such as any database of documents containing citations, the world wide web or any other hypermedia database. The rank assigned to a document is calculated from the ranks of documents citing it. In addition, the rank of a document is..."
