diff --git a/README.md b/README.md
index f163789..39fd69b 100644
--- a/README.md
+++ b/README.md
@@ -14,6 +14,7 @@ Middleware to use [FastRoute](https://github.com/nikic/FastRoute).
 * PHP >= 5.6
 * A [PSR-7](https://packagist.org/providers/psr/http-message-implementation) http mesage implementation ([Diactoros](https://github.com/zendframework/zend-diactoros), [Guzzle](https://github.com/guzzle/psr7), [Slim](https://github.com/slimphp/Slim), etc...)
 * A [PSR-15 middleware dispatcher](https://github.com/middlewares/awesome-psr15-middlewares#dispatcher)
+* Optionally, a [PSR-11](https://github.com/php-fig/container) container to resolve the route handlers
 
 ## Installation
 
@@ -56,8 +57,7 @@ $response = $dispatcher->dispatch(new ServerRequest('/hello/world'));
 * If the string is the name of a existing class (like: `Namespace\Class`) and contains the method `__invoke`, create a instance and execute that method.
 * Otherwise, treat it as a callable.
 
-If you want to change this behaviour, use a container implementing the [container-interop](https://github.com/container-interop/container-interop) to return the route callable.
-
+If you want to change this behaviour, use a container implementing the [PSR-11 spec](https://github.com/php-fig/container) to return the route callable.
 
 ## Options
 
@@ -65,9 +65,9 @@ If you want to change this behaviour, use a container implementing the [containe
 
 The dispatcher instance to use.
 
-#### `resolver(Interop\Container\ContainerInterface $resolver)`
+#### `resolver(Psr\Container\ContainerInterface $resolver)`
 
-To use a container implementing [container-interop](https://github.com/container-interop/container-interop) to resolve the route handlers.
+To use a container implementing [PSR-11 interface](https://github.com/php-fig/container) to resolve the route handlers.
 
 #### `arguments(...$args)`
 
diff --git a/src/FastRoute.php b/src/FastRoute.php
index 43795c5..0fd006f 100644
--- a/src/FastRoute.php
+++ b/src/FastRoute.php
@@ -2,6 +2,8 @@
 
 namespace Middlewares;
 
+use Middlewares\Utils\Factory;
+use Middlewares\Utils\CallableHandler;
 use Middlewares\Utils\CallableResolver\CallableResolverInterface;
 use Middlewares\Utils\CallableResolver\ContainerResolver;
 use Middlewares\Utils\CallableResolver\ReflectionResolver;
@@ -78,11 +80,11 @@ public function process(ServerRequestInterface $request, DelegateInterface $dele
         $route = $this->router->dispatch($request->getMethod(), $request->getUri()->getPath());
 
         if ($route[0] === Dispatcher::NOT_FOUND) {
-            return Utils\Factory::createResponse(404);
+            return Factory::createResponse(404);
         }
 
         if ($route[0] === Dispatcher::METHOD_NOT_ALLOWED) {
-            return Utils\Factory::createResponse(405);
+            return Factory::createResponse(405);
         }
 
         foreach ($route[2] as $name => $value) {
@@ -93,7 +95,7 @@ public function process(ServerRequestInterface $request, DelegateInterface $dele
 
         $callable = $this->getResolver()->resolve($route[1], $arguments);
 
-        return Utils\CallableHandler::execute($callable, $arguments);
+        return CallableHandler::execute($callable, $arguments);
     }
 
     /**