Not working with multiple fields

For example meta tag "citation_author" (from this specification). If paper have more then one auther it must be multiple.
But in function _metatags_quick_add_head have code:

 if (!empty($added_meta[$item['name']])) {
    return;
  }

It mean tag will be placed only once!
I think to solve this we must provide "delta" in function metatags_quick_field_formatter_view
example:

    case 'metatags_quick_default':
      foreach ($items as $delta => $item) {
        _metatags_quick_add_head(array(
          'type' => 'default',
          'name' => $item['meta_name'],
          'content' => $item['metatags_quick'],
          'entity' => $object,
          'entity_type' => $object_type,
          'delta' => $delta, // new array element
        ));
      }

And now instead

 if (!empty($added_meta[$item['name']])) {
    return;
  }

use

 if (!empty($added_meta[$item['name']][$item['delta']])) {
    return;
  }

and insted

    case 'default' :
      default :
        $element = array(
          '#tag' => 'meta', 
          '#attributes' => array(
            'name' => $item['name'], 
            'content' => $item['content']));
        drupal_add_html_head($element, 'metatags_quick_' . $item['name']);

use

    case 'default' :
      default :
        $element = array(
          '#tag' => 'meta', 
          '#attributes' => array(
            'name' => $item['name'], 
            'content' => $item['content']));
        drupal_add_html_head($element, 'metatags_quick_' . $item['name'].'_'.$item['delta']);

Please create patch if you want