awesome-php.md

@@ -345,7 +345,7 @@ A list of amazingly awesome PHP libraries, resources and shiny things.
 * [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) - A series about the PHP source code.
-* 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) - A series about the PHP garbage collection internals.
+* Collecting Garbage: [1](http://www.php.net/manual/en/features.gc.refcounting-basics.php) [2](http://www.php.net/manual/en/features.gc.collecting-cycles.php) [3](http://www.php.net/manual/en/features.gc.performance-considerations.php) - A series about the PHP garbage collection internals.
 * [Semantic Versioning](http://semver.org/) - A website explaining semantic versioning.
 * [Composer Primer](http://daylerees.com/composer-primer) - A Composer primer.
 * [Composer Versioning](https://igor.io/2013/01/07/composer-versioning.html) - An article about Composer versioning.