[1] Univ Aberdeen, Business Sch, Dept Econ, Aberdeen AB24 3QY, Scotland
[2] Univ Aberdeen, Business Sch, Aberdeen Ctr Res Energy Econ & Finance, Aberdeen AB24 3QY, Scotland
[3] Univ Dundee, Ctr Energy Petr & Mineral Law & Policy, Dundee DD1 4HN, Scotland
[4] Kings Coll London, Dept European & Int Studies, London WC2B 4BG, England
[5] Univ Manchester, Global Dev Inst, Manchester M13 9PL, England