rdiff-backup command restore with date

If a backup was made using rdiff-backup command for some particular date what is the format that should be given to restore the files for that particular date.

        rdiff-bakup -r "dateformat" backup/a.txt /destination-dir

Thanks..

From serverfault Hulk

• From the rdiff-backup(1) manual:

     5.     A date format of the form YYYY/MM/DD, YYYY-MM-DD, MM/DD/YYYY, or
            MM-DD-YYYY,  which  indicates  midnight  on the day in question,
            relative  to  the  current  timezone  settings.   For  instance,
            "2002/3/5",  "03-05-2002",  and  "2002-3-05" all mean March 5th,
            2002.
  

  From PowerSp00n