readme with improved links and pointers

readme.md

@@ -28,10 +28,12 @@ fi
 ```
 
 sources used to assemble this:
-* [madavi-api data\_simple.php airrohr sensor data API example](https://github.com/opendata-stuttgart/madavi-api/blob/master/data_simple.php) License not stated, but [recommended as starting point by author](https://forum.sensor.community/t/how-to-send-to-own-api/975/4)
+* [madavi-api data\_simple.php airrohr sensor data API example](https://github.com/opendata-stuttgart/madavi-api/blob/master/data_simple.php) License not stated, but [recommended as starting point by author](https://forum.sensor.community/t/how-to-send-to-own-api/975/4), and other works like [the corresponding firmware]()
 * [php-mqtt/client library's](https://github.com/php-mqtt/client) example code [01\_authorize\_with\_username\_and\_password.php](https://github.com/php-mqtt/client-examples/blob/master/03_connection_settings/01_authorize_with_username_and_password.php), both [MIT](https://github.com/php-mqtt/client/blob/master/LICENSE.md) [license](https://github.com/php-mqtt/client-examples/blob/master/LICENSE.md)
 
-The european Joinup Licensing Assistant [compatibility checker](https://joinup.ec.europa.eu/collection/eupl/solution/joinup-licensing-assistant/jla-compatibility-checker) states, that the permissive MIT license allows redistribution under other licenses, so [EUPL](https://joinup.ec.europa.eu/licence/compatibility-check/MIT/EUPL-1.2) is our choice.
+The european Joinup Licensing Assistant [compatibility checker](https://joinup.ec.europa.eu/collection/eupl/solution/joinup-licensing-assistant/jla-compatibility-checker) states, that the permissive [MIT license allows redistribution under other licenses](https://joinup.ec.europa.eu/licence/compatibility-check/MIT/EUPL-1.2), so here [EUPL-1.2](LICENSES/EUPL-1.2.txt) is our choice.
 
 Licenses handled and added via the great [reuse](https://reuse.software/) tool, thanks to all contributors of openly licensed source code and infrastucture!
 Shoutout for great dev/debug sessions with Alex.
+
+Such a functionality seems to have been already implemented elsewhere at [jklmnn/airrohr-mqtt](https://github.com/jklmnn/airrohr-mqtt) for Homeassistant.