Add a label and a seealso block.

Author: dunglas

components/serializer.rst

@@ -252,6 +252,8 @@ You are now able to serialize only attributes in the groups you want::
     $obj2 = $serializer->denormalize(array('foo' => 'foo', 'bar' => 'bar'), 'MyObj', null, array('groups' => array('group1', 'group3')));
     // $obj2 = MyObj(foo: 'foo', bar: 'bar')
 
+.. _ignoring-attributes-when-serializing:
+
 Ignoring Attributes
 -------------------
 
@@ -449,4 +451,10 @@ having unique identifiers::
     echo $serializer->serialize($org, 'json');
     // {"name":"Les-Tilleuls.coop","members":[{"name":"K\u00e9vin", organization: "Les-Tilleuls.coop"]}
 
+.. seealso::
+
+    A popular alternative to the Symfony Serializer Component is the third-party
+    library, `JMS serializer`_.
+
+.. _`JMS serializer`: https://github.com/schmittjoh/serializer
 .. _Packagist: https://packagist.org/packages/symfony/serializer