public static function exportModels($modelIds) {
        $dbWrapper = core_kernel_classes_DbWrapper::singleton();
        $result = $dbWrapper->query('SELECT DISTINCT "subject", "predicate", "object", "l_language" FROM "statements" 
            WHERE "modelid" IN (\''.implode('\',\'', $modelIds).'\')');
        	
        common_Logger::i('Found '.$result->rowCount().' entries for models '.implode(',', $modelIds));
        return self::statement2rdf($result);
    }