public function findOauthConsumerResource($consumer_key)
	{
		$returnValue = null;

		$class = $this->getClass(self::CLASS_URI_OAUTH_CONSUMER);
		$instances = $class->searchInstances(array(self::PROPERTY_OAUTH_KEY => $consumer_key), array('like' => false, 'recursive' => true));
		if (count($instances) == 0) {
			throw new \tao_models_classes_oauth_Exception('No Credentials for consumer key '.$consumer_key);
		}
		if (count($instances) > 1) {
			throw new \tao_models_classes_oauth_Exception('Multiple Credentials for consumer key '.$consumer_key);
		}
		$returnValue	= current($instances);

		return $returnValue;
	}