Want to understand how browsers parse, compute, and output webpages as an attempt to compare how Webkit (safari and chrome) and Firefox (gecko) function.
Given that all of these rending engines / browsers are open source, I figure there would be documentation, schematics / diagrams, or other forms of explanation, but I cant find anything that is hight level or easy to understand (im not a programmer, but have a high degree of technical knowledge).

I have found the following webpages:

http://www.vineetgupta.com/tag/browser-architecture/

http://taligarsiel.com/Projects/howbrowserswork1.htm

but Id like to find more like these. any suggestions?