7. A method for natural language processing of input text comprising: processing the text to identify a group of candidate titles of works; identifying verbs which are used to introduce direct speech; filtering the group of candidate titles of works, including applying at least one rule which is formulated to remove candidate titles of works which are citations of direct speech from the group of candidate titles of works, the filtering comprising filtering out expressions linked to a verb identified as being one of the verbs which are used to introduce direct speech; comparing remaining candidate titles of works with a knowledge base which identifies titles of works; for a candidate title of a work which matches a title of a work in the knowledge base, annotating the text to identify the candidate title of a work as a nominative unit; and wherein the filtering, processing, comparing, and annotating are all implemented by a digital processor.
7. A method for natural language processing of input text comprising: processing the text to identify a group of candidate titles of works; identifying verbs which are used to introduce direct speech; filtering the group of candidate titles of works, including applying at least one rule which is formulated to remove candidate titles of works which are citations of direct speech from the group of candidate titles of works, the filtering comprising filtering out expressions linked to a verb identified as being one of the verbs which are used to introduce direct speech; comparing remaining candidate titles of works with a knowledge base which identifies titles of works; for a candidate title of a work which matches a title of a work in the knowledge base, annotating the text to identify the candidate title of a work as a nominative unit; and wherein the filtering, processing, comparing, and annotating are all implemented by a digital processor. 13. The method of claim 7 , wherein the processing includes dividing the text into an ordered sequence of tokens, associating parts of speech with the tokens, and identifying any expressions, each comprising at least one of the tokens, which are distinguished from adjacent tokens in a manner used to identify titles of works.