public function getAuthorisedViewLevels()
	{
		if (is_null($this->authLevels))
		{
			$this->authLevels = array();
		}

		if (empty($this->_authLevels))
		{
			$this->authLevels = Access::getAuthorisedViewLevels($this->get('id'));
		}

		return $this->authLevels;
	}