6. The computer-assisted method of claim 1 , further comprising: obtaining a data set comprising a plurality of external term prominence (ETP) values each associated with one of the plurality of tokens including the jth token, wherein the ETP value is calculated using external documents different from the first document, wherein the term prominence value for the jth token is calculated using the ITP and the ETP values of the jth token.
6. The computer-assisted method of claim 1 , further comprising: obtaining a data set comprising a plurality of external term prominence (ETP) values each associated with one of the plurality of tokens including the jth token, wherein the ETP value is calculated using external documents different from the first document, wherein the term prominence value for the jth token is calculated using the ITP and the ETP values of the jth token. 11. The computer-assisted method of claim 6 , wherein the external documents are randomly selected.