code: def Extra(self):
          
          extraTags = ['V', 'P', 'DOI', 'misc']
          retVal = ""
          for tag in extraTags:
              if getattr(self, tag):
                  retVal += getattr(self, tag) + ', '
          if len(retVal) > 2:
              return retVal[:-2]
          else:
              return retVal
docs: Returns any `V`, `P`, `DOI` or `misc` values as a string. These are all the values not returned by [ID()](#metaknowledge.citation.Citation.ID), they are separated by `' ,'`.
  
          # Returns
  
          `str`
  
          > A string containing the data not in the ID of the `Citation`.