States as international persons — Recognition — Of States — Taiwan — International Amateur Athletic Federation — Membership limited to one association from each “country” — Admission to membership of association from People's Republic of China — Resultant exclusion of Taiwan association — Whether valid under rules of Federation — Non-recognition of Taiwan by United Kingdom — Relevance — Whether Taiwan a “country” for purposes of Federation rules — Whether “State” co-extensive with “country” — Construction of Rules — Whether surrounding circumstances should be taken into account — The law of England