function getSubfield($code = null, $pcre = null)
    {
        // iterate merrily through the subfields looking for the requested code
        foreach ($this->subfields as $sf) {
            if (($pcre
                && preg_match("/$code/", $sf->getCode()))
                || (!$pcre
                && $code == $sf->getCode())
            ) {
                return $sf;
            }
        }

        // No matches were found
        return false;
    }