8 For the methodical issues related to the evolution of transnational principles of law, see generally A Metzger, Extra legem, intra ius: Allgemeine Rechtsgrundsätze im Europäischen Privatrecht (Tübingen, Mohr Siebeck Verlag 2009) 244 et seq.
9 See JR Crook, 'Applicable Law in International Commercial Arbitration: The Iran-US-Claims Tribunal Experience' (1989) 83 AJIL 278, 293 et seq.; JA Westberg, 'Contract Excuse in International Business Transactions: Award of the Iran-United States Claims Tribunal' (1989) 4 ICSID Review-FILR 215 et seq.