Primary: B - Mining and quarrying
6 - Extraction of crude petroleum and natural gas
http://globalarbitrationreview.com/news/article/33910/failed-pipeline-developer-takes-turkey/ (requires subscription)
http://www.iareporter.com/articles/turkey-faces-international-arbitration-brought-by-nabucco-gas-pipeline-international-gmbh/ (requires subscription)
http://globalarbitrationreview.com/news/article/34485/breakaway-firm-opens-vienna/ (requires subscription)
http://www.juve.de/nachrichten/oesterreich/2015/11/nabucco-streit-pipeline-setzt-bei-vergleich-mit-tuerkei-auf-hilfe-von-specht
https://energycharter.org/what-we-do/dispute-settlement/investment-dispute-settlement-cases/72-nabucco-gas-pipeline-international-gmbh-in-liqu-v-turkey/