diff --git a/pihole/README b/pihole/README
index eee377e..2972e04 100644
--- a/pihole/README
+++ b/pihole/README
@@ -30,6 +30,10 @@ You should change this on first use, by running:
 `pihole -a -p`
 
 
+The implementation is based on work by Patrizio Tufarolo, 
+(https://blog.tufarolo.eu/how-to-configure-pihole-in-qubesos-proxyvm/ ), 
+and updated for Qubes 4.1
+
   for i in `qvm-ls -O NAME,NETVM | awk '/ sys-firewall/{ print $1 }'`; do qvm-prefs $i netvm sys-pihole; done
   if [[ $(qubes-prefs default_netvm sys-firewall |grep sys-firewall ) ]]; then qubes-prefs default_netvm sys-pihole; fi