diff --git a/FAQ.md b/FAQ.md
index c56022a..0ec86f3 100644
--- a/FAQ.md
+++ b/FAQ.md
@@ -1620,6 +1620,9 @@ For normal non-admin user, the device list on web console only shows devices ass
 
 # Device group vs address book
 
-The device groups are actually security groups, to restrict access to certain machines from internal team.
+The device groups are actually security groups used to restrict which users can access which group of devices (aka ACL).
+https://rustdesk.com/docs/en/self-host/rustdesk-server-pro/permissions/
 
-Address books are used to organize devices and manage passwords.
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+Address books are used to organize devices and manage passwords.
+
+https://github.com/rustdesk/rustdesk-server-pro/discussions/809
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