diff --git a/right-fit-swap-for-laptop-hibernation-Ubuntu-20.04-full-ZFS-install.md b/right-fit-swap-for-laptop-hibernation-Ubuntu-20.04-full-ZFS-install.md
index 3b8b173..e310a54 100644
--- a/right-fit-swap-for-laptop-hibernation-Ubuntu-20.04-full-ZFS-install.md
+++ b/right-fit-swap-for-laptop-hibernation-Ubuntu-20.04-full-ZFS-install.md
@@ -103,6 +103,8 @@ HandleLidSwitch=suspend-then-hibernate
 
 ## encrypt swap partition
 
+source : [wiki.archlinux.org - dm-crypt/Swap encryption](https://wiki.archlinux.org/index.php/Dm-crypt/Swap_encryption#LVM_on_LUKS)
+
 ~~~
 apt-get install ecryptfs-utils
 swapoff -a