Fair and equitable treatment/Minimum standard of treatment, including denial of justice claims
Umbrella clause
Arbitrary, unreasonable and/or discriminatory measures
http://globalarbitrationreview.com/article/1067578/venezuela-claim-gets-all-clear-thanks-to-mfn (requires subscription)
http://www.iareporter.com/articles/majority-of-tomka-and-fortier-allow-investor-to-use-an-mfn-clause-to-pursue-uncitral-arbitration-against-venezuela/ (requires subscription)
https://www.iareporter.com/articles/analysis-tomka-chaired-tribunal-finds-violation-of-non-impairment-standard-but-dismisses-remaining-claims-arising-out-of-venezuelan-oil-and-gas-investment/ (requires subscription)