code: def bib_name(self):
          
          bib_name = None
          for match in texutils.bib_pattern.finditer(self.text):
              bib_name = match.group(1)
              if not bib_name.endswith('.bib'):
                  bib_name = ".".join((bib_name, "bib"))
          return bib_name
docs: Name of the BibTeX bibliography file (e.g.,
          ``'mybibliography.bib'``).