diff --git a/2021/zfs-snapshots.md b/2021/zfs-snapshots.md
index c316560..adc55c3 100644
--- a/2021/zfs-snapshots.md
+++ b/2021/zfs-snapshots.md
@@ -1,5 +1,7 @@
 # ZFS snapshots
 
+Docs: https://github.com/bdrewery/zfstools
+
 ```
 pkg install zfstools
 ```