public function get($documentId, $cache = true)
    {
        $rtn = $this->getCache($documentId);

        if (!$cache || !$rtn) {
            list($status, $doc) = $this->sendRequest(urlencode($documentId));

            if ($status == 200) {
                $rtn = $this->setCache($documentId, $doc);
            } else {
                $rtn = null;
            }
        }

        return $this->asDocs ? $this->toDocument($rtn) : $rtn;
    }