static public function initialize($dsn = null, $user = null, $config = array(), $return_boolean = true)
	{
		static $instance;
		if (empty($instance))
		{
			if (empty($dsn))
			{
				return false;
			}

			$instance = new QuickBooks_WebConnector_Queue($dsn, $user, $config);
		}

		if ($return_boolean and $instance)
		{
			return true;
		}

		return $instance;
	}