added missing links

Author: fabpot

book/part01.rst

@@ -1,7 +1,7 @@
 Introduction
 ============
 
-Symfony2 is a reusable set of standalone, decoupled, and cohesive PHP
+`Symfony2`_ is a reusable set of standalone, decoupled, and cohesive PHP
 components that solve common web development problems.
 
 Instead of using these low-level components, you can use the ready-to-be-used
@@ -150,6 +150,7 @@ start with the simplest web application we can think of in PHP::
 That's all for the first part of this series. Next time, we will introduce the
 HttpFoundation Component and see what it brings us.
 
+.. _`Symfony2`:                  http://symfony.com/
 .. _`documentation`:             http://symfony.com/doc
 .. _`Silex`:                     http://silex.sensiolabs.org/
 .. _`autoload`:                  http://fr.php.net/autoload

book/part12.rst

@@ -254,9 +254,10 @@ great details, but hopefully it gives you enough information to get started on
 your own and to better understand how the Symfony2 framework works internally.
 
 If you want to learn more, I highly recommend you to read the source code of
-the Silex micro-framework, and especially its `Application`_ class.
+the `Silex`_ micro-framework, and especially its `Application`_ class.
 
 Have fun!
 
 .. _`Pimple`:      https://github.com/fabpot/Pimple
+.. _`Silex`:       https://silex.sensiolabs.org/
 .. _`Application`: https://github.com/fabpot/Silex/blob/master/src/Silex/Application.php