diff --git a/docs/api.markdown b/docs/api.markdown
--- a/docs/api.markdown
+++ b/docs/api.markdown
@@ -43,7 +43,7 @@ Parameters:
 * ``last_update``: last update timestamp
 * ``last_post``: last added post id
 
-Get the diff of the thread in the `O`` 
+Get the diff of the thread in the ``O`` 
 format. 2 formats are available: ``html`` (used in AJAX thread update) and 
 ``json``. The default format is ``html``. Return list format: