diff --git a/pages/common/unexpand.md b/pages/common/unexpand.md
index be29d3973e..07c8d5656c 100644
--- a/pages/common/unexpand.md
+++ b/pages/common/unexpand.md
@@ -1,6 +1,7 @@
 # unexpand
 
 > Convert spaces to tabs.
+> More information: <https://www.gnu.org/software/coreutils/manual/html_node/unexpand-invocation.html>.
 
 - Convert blanks in each file to tabs, writing to standard output: