diff --git a/Doc/library/asyncio-protocol.rst b/Doc/library/asyncio-protocol.rst
index 5e6b5b4..f08738d 100644
--- a/Doc/library/asyncio-protocol.rst
+++ b/Doc/library/asyncio-protocol.rst
@@ -73,7 +73,7 @@
 various kinds of communication channels.
 
 Transport objects are always instantiated by an
-ref:`asyncio event loop <asyncio-event-loop>`.
+:ref:`asyncio event loop <asyncio-event-loop>`.
 
 asyncio implements transports for TCP, UDP, SSL, and subprocess pipes.
 The methods available on a transport depend on the transport's kind.