text: '''
  Conversion of references to ris format
  '''
  
  
  def write_ris(key, ref):
      '''Convert a single reference to ris format
      '''
      s = ''
  
      s += '#{} {}\n'.format(ref['_entry_type'], key)
      if ref['_entry_type'] == 'article':
          s += "TY Journal Article \n"
      elif ref['_entry_type'] == 'misc':
          s += "TY Generic \n"
      elif ref['_entry_type'] == 'unpublished':
          s += "TY Unpublished \n"
      elif ref['_entry_type'] == 'incollection':
          s += "TY Book \n"
      elif ref['_entry_type'] == 'phdthesis':
          s += "TY Thesis \n"
      elif ref['_entry_type'] == 'techreport':
          s += "TY Report \n"
      else:
          s += "TY Generic\n"
  
      entry_lines = []
      for k, v in ref.items():
          if k == '_entry_type':
              continue
  
          # Handle authors/editors
          if k == 'authors':
              for author in v:
                  entry_lines.append('AU {}'.format(author))
          elif k == 'year':
              entry_lines.append('PY {}'.format(v))
          elif k == 'journal':
              entry_lines.append('JO {}'.format(v))
          elif k == 'volume':
              entry_lines.append('VL {}'.format(v))
          elif k == 'pages':
              entry_lines.append('SP {}'.format(v))
          elif k == 'title':
              entry_lines.append('T1 {}'.format(v))
          elif k == 'doi':
              entry_lines.append('DO {}'.format(v))
          else:
              entry_lines.append('N1 {}:{}'.format(k, v))
  
      s += '\n'.join(entry_lines)
      s += '\n'
  
      return s
  