There are many, many interesting things in the DTD reference box.
I have talked about some of them, others I have not.
For example, 031 just hit New York.
Notice how the three digits (0, 3, 1) were at the bottom of the reference box going back 10 numbers from the 357.
Actually, it had two 0s, two 3s, and two 1s.
The DTD reference box is full of these idiosyncrasies. They deserve more study.
