awesome-php.md

@@ -348,4 +348,5 @@ A list of amazingly awesome PHP libraries, resources and shiny things.
 * [Innocent Villagefolk or a Pillagin’ Pirate?](http://blog.astrumfutura.com/2012/04/php-innocent-villagefolk-or-a-pillagin-pirate/) - An article about PHP taking ideas from other language.
 * [Predicting Random Numbers in PHP](http://blog.astrumfutura.com/2013/03/predicting-random-numbers-in-php-its-easier-than-you-think/) - An article about generating random numbers.
 * [C is for Cookie, H is for Hacker](http://www.troyhunt.com/2013/03/c-is-for-cookie-h-is-for-hacker.html) - An article about cookies and security.
-* [A 20 Point List for Preventing XSS in PHP](http://blog.astrumfutura.com/2013/04/20-point-list-for-preventing-cross-site-scripting-in-php/) - An article about preventing XSS.
+* [A 20 Point List for Preventing XSS in PHP](http://blog.astrumfutura.com/2013/04/20-point-list-for-preventing-cross-site-scripting-in-php/) - An article about preventing XSS.
+* [A Beginners Guide to HTTP Cache Headers](http://www.mobify.com/blog/beginners-guide-to-http-cache-headers/) - An article about HTTP cache headers.