diff --git a/README.md b/README.md
index 6605276..69ac959 100644
--- a/README.md
+++ b/README.md
@@ -127,7 +127,7 @@ For more information see [here](https://modemmanager.org/docs/modemmanager/debug
 
 ### SIP
 
-This plugin uses the libsofia-sip library for SIP signalling and
+This plugin uses the [sofia-sip][] library for SIP signalling and
 GStreamer for media handling. It supports multiple SIP accounts and
 currently one active call at a time (subject to change).
 
@@ -154,3 +154,5 @@ incoming call you should send a `USR1` signal to the calls process:
 
 This plugin is not in active development anymore, so your mileage may vary.
 See [here](ofono.md) for more information.
+
+[sofia-sip]: https://github.com/BelledonneCommunications/sofia-sip