11. A computer system as in claim 6 , wherein at least one of said one or more databases is an XML-based database.
11. A computer system as in claim 6 , wherein at least one of said one or more databases is an XML-based database. 12. A computer system as in claim 11 , wherein said XML based database is operable to be searched using XQuery statements that count how many publication in a specified publication year cite to a specified publication.