README.md

@@ -10,6 +10,9 @@
 - https://www.richis-lab.de/Siedle.htm
 - https://esphome.io/guides/getting_started_hassio.html
 - https://community.home-assistant.io/t/sss-siedle-hta-811-door-phone-notify-in-ring/405179
+- https://github.com/chrta/sip_call
+- https://www.mikrocontroller.net/topic/442157
+- https://gist.github.com/denalena/b043b2f46fe9475c37c01a16c923efc3
 
 ## Potential entry points
 - Wifi -> fritz.box -> sip