diff --git a/docs/source/libtutorial.rst b/docs/source/libtutorial.rst
index 13f43e3f..080e3817 100644
--- a/docs/source/libtutorial.rst
+++ b/docs/source/libtutorial.rst
@@ -289,6 +289,10 @@ and then assign it to your Task.
 
     .. code-block:: python
 
+        from aeneas.task import Task
+        from aeneas.textfile import TextFile, TextFragment
+        from aeneas.language import Language
+
         task = Task()
         textfile = TextFile()
         for identifier, frag_text in [