Do Currency Unions Grow Too Large For Their Own Good?
论证货币区扩大时边际成本上升会超过边际收益，且现有成员短视投票导致联盟超出最优规模，但一个货币联盟的存在不影响其他联盟的组建或扩张。
This article puts a rigorous foundation under the proposition that currency areas, as they admit more members, face a rising marginal cost curve which cuts the marginal benefit curve from below. However, at any given time, the median member faces lower marginal cost than the average member, so that, if new members are admitted by majority vote, and existing members are myopic, the currency area will expand beyond its optimum size. Although the currency area imposes negative externalities on countries outside it, we find that the existence of one currency union has no effect on the costs or benefits of forming or enlarging another.