private function buildBaseString($baseURI, $method, $params)
    {
        $return = array();
        ksort($params);

        foreach($params as $key => $value)
        {
            $return[] = rawurlencode($key) . '=' . rawurlencode($value);
        }

        return $method . "&" . rawurlencode($baseURI) . '&' . rawurlencode(implode('&', $return));
    }