diff --git a/script/lib/chrooted_job_ubuntu.sh b/script/lib/chrooted_job_ubuntu.sh
index 6d8cd57..5cdd73b 100644
--- a/script/lib/chrooted_job_ubuntu.sh
+++ b/script/lib/chrooted_job_ubuntu.sh
@@ -29,7 +29,8 @@ function chrooted_job() {
 	echo "${CRYPTPARTNAME} UUID=$(blkid -s UUID -o value ${DEV}${CRYPTPARTITION}) /etc/luks/boot_os.keyfile luks,discard" >> /etc/crypttab
 
 	# Add key file to the list of the intems in initfsram. 
-	echo "...Registering key file to the ramfs"
+	# See https://cryptsetup-team.pages.debian.net/cryptsetup/README.initramfs.html for detail
+	echo "...Directing to include keyfile into the initfsram"
 	echo "KEYFILE_PATTERN=/etc/luks/*.keyfile" >> /etc/cryptsetup-initramfs/conf-hook
 	echo "UMASK=0077" >> /etc/initramfs-tools/initramfs.conf
 
diff --git a/script/lib/chrooted_job_void.sh b/script/lib/chrooted_job_void.sh
index 9ce0c82..2bed1d5 100644
--- a/script/lib/chrooted_job_void.sh
+++ b/script/lib/chrooted_job_void.sh
@@ -29,7 +29,8 @@ function chrooted_job() {
 	echo "${CRYPTPARTNAME} UUID=$(blkid -s UUID -o value ${DEV}${CRYPTPARTITION}) /etc/luks/boot_os.keyfile luks,discard" >> /etc/crypttab
 
 	# Add key file to the list of the intems in initfsram. 
-	echo "...Registering key file to the ramfs"
+	# See https://man7.org/linux/man-pages/man5/dracut.conf.5.html for details.
+	echo "...Directing to include keyfile into the initfsram"
 	echo 'install_items+=" /etc/luks/boot_os.keyfile /etc/crypttab " ' > /etc/dracut.conf.d/10-crypt.conf
 
 	# Finally, update the ramfs initial image with the key file.