protected function _getReferenceContainer($config)
    {
        try {
            $container = $this->_containerHas($config, static::K_REFERENCE_CONTAINER)
                ? $this->_containerGet($config, static::K_REFERENCE_CONTAINER)
                : $this->_getContainer();
        } catch (RootException $e) {
            throw $this->_createRuntimeException('Could not retrieve a valid referencing container');
        }

        return $container;
    }