protected function _getFieldLongName($sFieldName)
    {
        $aFieldNames = [
            'oxorderfiles__oxarticletitle',
            'oxorderfiles__oxarticleartnum',
            'oxorderfiles__oxordernr',
            'oxorderfiles__oxorderdate',
            'oxorderfiles__oxispaid',
            'oxorderfiles__oxpurchasedonly'
        ];

        if (in_array($sFieldName, $aFieldNames)) {
            return $sFieldName;
        }

        return parent::_getFieldLongName($sFieldName);
    }