diff --git a/ssh/agent/client.go b/ssh/agent/client.go
index acb5ad8..b1808dd 100644
--- a/ssh/agent/client.go
+++ b/ssh/agent/client.go
@@ -8,7 +8,7 @@
 // ssh-agent process using the sample server.
 //
 // References:
-//  [PROTOCOL.agent]:    http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/PROTOCOL.agent?rev=HEAD
+//  [PROTOCOL.agent]: https://tools.ietf.org/html/draft-miller-ssh-agent-00
 package agent // import "golang.org/x/crypto/ssh/agent"
 
 import (