private function listResources($filters = array(), $listType = null)
    {
        $uri = '/resources';
        $query = array();
        if ($listType) {
            $query[] = $listType;
        }
        foreach ($filters as $name => $value) {
            $query[] = "{$name}={$value}";
        }

        if (sizeof($query)) {
            $uri .= '?' . implode('&', $query);
        }
        $body = $this->sendRequest($uri);
        $node = $this->parseXml((string)$body);
        return $this->parseResourcesXmlToResources($node);
    }