diff --git a/doc/index.md b/doc/index.md
index 1f99b39..c6bc44b 100644
--- a/doc/index.md
+++ b/doc/index.md
@@ -11,7 +11,7 @@ available with OpenType (and other) fonts, including upper and lower case number
 proportional and monospaced numbers, swash letters, ligature control, and many
 many others.
 
-See the documentation `fontspec.pdf` for full information.
+See the documentation `fontspec.pdf` ([CTAN version](http://mirrors.ctan.org/macros/unicodetex/latex/fontspec/fontspec.pdf), or [Github prerelease version](http://latex3.github.io/fontspec/fontspec.pdf)) for full information.
 
 * [Summary of user commands](user.html)
 * [Package installation details](install.html)