It is the date of creating this bibliographic record. This field should include the complete title with all the subtitles, if any. Revision information consists of an integer followed by a comma, and by text in an open ended format. The revised bibliographic record should contain a complete record for the publication, not just a list of changes to the old record. The first token in this field is an integer revision number.
Higher numbers indicate later revisions.
Use the text to describe the revision. A withdrawal of a record is a special case of revising it. This new record will replace all the fields of the previous record for that publication. In this example it will eliminate the title, the retrieval information provided earlier, and not mention the authors. Normal last name first inversion.