diff --git a/Type Juggling/README.md b/Type Juggling/README.md
index 26dcfd1..7ceaf0b 100644
--- a/Type Juggling/README.md	
+++ b/Type Juggling/README.md	
@@ -100,4 +100,5 @@ var_dump(sha1('aaO8zKZF') == sha1('aa3OFF9m'));
 ## References
 
 * [Writing Exploits For Exotic Bug Classes: PHP Type Juggling By Tyler Borland](http://turbochaos.blogspot.com/2013/08/exploiting-exotic-bugs-php-type-juggling.html)
-* [Magic Hashes - WhieHatSec](https://www.whitehatsec.com/blog/magic-hashes/)
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+* [Magic Hashes - WhieHatSec](https://www.whitehatsec.com/blog/magic-hashes/)
+* [PHP Magic Tricks: Type Juggling](https://owasp.org/www-pdf-archive/PHPMagicTricks-TypeJuggling.pdf)
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