wikipedia articles url rewrite rules
Is there any one know, what is the url rewrite rule in wikipedia article's url?

I find some thing:

`and`, `of` ,`in`... all the conjunction write in lowercase.

The `place name`, `people name`, `history event name`, all the first letter would be capitalize.

http://en.wikipedia.org/wiki/New_York_City

http://en.wikipedia.org/wiki/Abraham_Lincoln  

http://en.wikipedia.org/wiki/American_Civil_War

but sometimes only the first letter would be capitalize.

http://en.wikipedia.org/wiki/Digestive_system

So what a complex rewrite system wikipedia had, and how many codes make it run?

I have download one mediawiki system, from http://www.mediawiki.org/wiki/Download. But for my ability, I can not find anything in `.htaccess` or `php code`.  
wikipedia articles url rewrite rules
===

Is there any one know, what is the url rewrite rule in wikipedia article's url?

I find some thing:

`and`, `of` ,`in`... all the conjunction write in lowercase.

The `place name`, `people name`, `history event name`, all the first letter would be capitalize.

http://en.wikipedia.org/wiki/New_York_City

http://en.wikipedia.org/wiki/Abraham_Lincoln  

http://en.wikipedia.org/wiki/American_Civil_War

but sometimes only the first letter would be capitalize.

http://en.wikipedia.org/wiki/Digestive_system

So what a complex rewrite system wikipedia had, and how many codes make it run?

I have download one mediawiki system, from http://www.mediawiki.org/wiki/Download. But for my ability, I can not find anything in `.htaccess` or `php code`.  