code: def get_reference_section_beginning(fulltext):
      
      sect_start = {
          'start_line': None,
          'end_line': None,
          'title_string': None,
          'marker_pattern': None,
          'marker': None,
          'how_found_start': None,
      }
  
      # Find start of refs section:
      sect_start = find_reference_section(fulltext)
      if sect_start is not None:
          sect_start['how_found_start'] = 1
      else:
          # No references found - try with no title option
          sect_start = find_reference_section_no_title_via_brackets(fulltext)
          if sect_start is not None:
              sect_start['how_found_start'] = 2
          # Try weaker set of patterns if needed
          if sect_start is None:
              # No references found - try with no title option (with weaker
              # patterns..)
              sect_start = find_reference_section_no_title_via_dots(fulltext)
              if sect_start is not None:
                  sect_start['how_found_start'] = 3
              if sect_start is None:
                  # No references found - try with no title option (with even
                  # weaker patterns..)
                  sect_start = find_reference_section_no_title_via_numbers(
                      fulltext)
                  if sect_start is not None:
                      sect_start['how_found_start'] = 4
  
      if sect_start:
          current_app.logger.debug('* title %r' % sect_start['title_string'])
          current_app.logger.debug('* marker %r' % sect_start['marker'])
          current_app.logger.debug('* title_marker_same_line %s'
                                   % sect_start['title_marker_same_line'])
      else:
          current_app.logger.debug('* could not find references section')
      return sect_start
docs: Get start of reference section.