This article is from the RSC/UKSC Cricket FAQ, by Ganesh with numerous contributions by others.
The official site of _The Association of Cricket Statisticians
& Historians_ is another useful resource
It is Ian T's firm belief that the site recommended
by Terry Walsh next IS FULL OF MISTAKES!!
It certainly does not reflect changes to symbols made in
1985? or ANY 2000 code changes.
ACB & Qld Cricket scorer Judy Harris has produced
a guide that I think will fit your criteria. It has
everything you'll need (hopefully) including examples.