Help - GUI Scripting Reference?

I am looking for some assistance (e.g., discussion and examples) with scripting via System Events and the GUI. I’ve kind of figured out the UI browser, but need info on the options for controlling the identified GUI elements. In particular, I’d like more info on the ‘perform’, ‘keystroke’ and ‘key code’ terms. I’m also looking for a way to do a ‘command-click’ and ‘double-click’ through Applescript.

Are there any good GUI scripting references on this website, or elsewhere on the web? (I already have read the Apple pages I could find.) How about in any of the Applescript books out there?

many thanks,