经济学家阿曼·哈默提出过一个市场法则：国家、地区之间的风俗、传统、习惯、生活方式和社会制度等的差异越大，潜在的市场就越大。 20世纪 20年代，苏维埃俄国由于连年的国内战争和外国武装力量的干涉、封锁，食品供应非常紧张。而美国当时粮食连年丰收，价格相当低，每蒲耳 The economist Oman Hammer has proposed a market rule: The greater the difference between the customs, traditions, habits, lifestyles and social systems among countries and regions, the greater the potential market. In the 1920s, Soviet Russia was very nervous because of years of internal war and interference and blockade by foreign armed forces. While the United States harvested food at the time, the price was quite low, at a rate of