awesome-php.md

@@ -149,4 +149,5 @@ A list of amazingly awesome PHP libraries that you should consider using (and so
 * [Understanding OpCodes](http://blog.golemon.com/2008/01/understanding-opcodes.html) - An article about opcodes.
 * [When Does Foreach Copy?](http://nikic.github.com/2011/11/11/PHP-Internals-When-does-foreach-copy.html) - An article about the internals of foreach.
 * [How Big Are PHP Arrays (And Values) Really?](http://nikic.github.com/2011/12/12/How-big-are-PHP-arrays-really-Hint-BIG.html) - An article about array internals.
-* PHP Source Code for Developers: [1](http://blog.ircmaxell.com/2012/03/phps-source-code-for-php-developers.html) [2](http://nikic.github.com/2012/03/16/Understanding-PHPs-internal-function-definitions.html) [3](http://blog.ircmaxell.com/2012/03/phps-source-code-for-php-developers_21.html) [4](http://nikic.github.com/2012/03/28/Understanding-PHPs-internal-array-implementation.html)
+* PHP Source Code for Developers: [1](http://blog.ircmaxell.com/2012/03/phps-source-code-for-php-developers.html) [2](http://nikic.github.com/2012/03/16/Understanding-PHPs-internal-function-definitions.html) [3](http://blog.ircmaxell.com/2012/03/phps-source-code-for-php-developers_21.html) [4](http://nikic.github.com/2012/03/28/Understanding-PHPs-internal-array-implementation.html)
+* Collecting Garbage: [1](http://derickrethans.nl/collecting-garbage-phps-take-on-variables.html) [2](http://derickrethans.nl/collecting-garbage-cleaning-up.html) [3](http://derickrethans.nl/collecting-garbage-performance-considerations.html)