Export problem of references

NativeImportDom.inc.php:
if (($node = $articleNode->getChildByName('citations'))) $article->setCitations($node->getValue());
NativeExportDom.inc.php:
XMLCustomWriter::createChildWithText($doc, $root, 'pages', $article->getPages(), false);
		XMLCustomWriter::createChildWithText($doc, $root, 'citations', $article->getCitations(), false); 
		$fullTextUrl =& XMLCustomWriter::createChildWithText($doc, $root, 'fullTextUrl', Request::url(null, 'article', 'view', $article->getId()));
		XMLCustomWriter::setAttribute($fullTextUrl, 'format', 'html');
native.dtd:
<!ELEMENT article (id*, title+, abstract*, indexing?, sponsor*, author+, pages?, citations, date_published, open_access?, (galley?, htmlgalley?)+, supplemental_file*)>
<!ELEMENT citations (#PCDATA)>
As described here:
https://github.com/hussar/ojs/commit/7c5858bafc74bb0e7b25032780cff9862ead3eeb