function formatField($exclude = array('2'))
    {
        if ($this->isControlField()) {
            return $this->getData();
        } else {
            $out = '';
            foreach ($this->getSubfields() as $subfield) {
                if (substr($this->getTag(), 0, 1) == '6' and (in_array($subfield->getCode(), array('v','x','y','z')))) {
                    $out .= ' -- ' . $subfield->getData();
                } elseif (!in_array($subfield->getCode(), $exclude)) {
                    $out .= ' ' . $subfield->getData();
                }
            }
            return trim($out);
        }
    }