https://www.lobbycontrol.de/wp-content/uploads/gaslobby-studie-lobbycontrol.pdf
https://www.occrp.org/en/suisse-secrets/
https://wiiw.ac.at/still-in-the-fast-lane-how-can-eu-cee-get-its-groove-back-dlp-6997.pdf
https://www.occrp.org/en/daily/11936-russian-ventilator-suppliers-may-be-conspiring-to-avoid-competition