public function normalize()
    {
        $values = $this->toArray();

        for ($i = 0, $total = count($values); $i < $total; $i++) {
            if (strpos($values[$i], $this->glue) !== false) {
                // Explode on glue when the glue is not inside of a comma
                foreach (preg_split('/' . preg_quote($this->glue) . '(?=([^"]*"[^"]*")*[^"]*$)/', $values[$i]) as $v) {
                    $values[] = trim($v);
                }
                unset($values[$i]);
            }
        }

        $this->values = array_values($values);

        return $this;
    }