Netherlands
http://www.energycharter.org/what-we-do/dispute-settlement/investment-dispute-settlement-cases/93-engie-sa-gdf-international-sas-and-engie-international-holdings-bv-v-hungary/
http://globalarbitrationreview.com/article/1036274/hungary-faces-new-energy-charter-treaty-claim (requires subscription)
http://nol.hu/gazdasag/szazmilliardos-per-a-magyar-allam-ellen-1611259
https://www.iareporter.com/articles/hungary-sees-new-icsid-arbitration-claim-from-energy-investors/ (requires subscription)