https://www.iareporter.com/articles/german-construction-giant-sues-saudi-arabia-under-bilateral-investment-treaty/ (requires subscription)
https://globalarbitrationreview.com/article/1169207/hochtief-files-claim-against-saudi-arabia (requires subscription)
http://saudi-commerce.com.sa/newsdetailspage/2017/07/04/saudi-turkish-jv-wins-riyadh-airport-expansion-contract
https://www.iareporter.com/articles/investment-treaty-claim-over-refurbishing-of-riyadh-airport-is-discontinued/ (requires subscription)
https://globalarbitrationreview.com/article/1196784/hochtief-withdraws-icsid-claim-against-saudi-arabia (requires subscription)