From d9d0b8444b67bad9efe53de6f2990a57fc5a6772 Mon Sep 17 00:00:00 2001
From: Alan Donovan
+ p.222. Exercise 8.1: the port numbers for London
+ and Tokyo should be swapped in the final command to
+ match the earlier commands.
+ (Thanks to Kiyoshi Kamishima, 2016-01-08.)
+
p.347, Exercise 12.8: for "like json.Marshal",
read "like json.Unmarshal".