A Wolfram in Sheep's Clothing: Economic Warfare in Spain, 1940–1944
研究了二战期间美国通过公开市场购买西班牙钨矿（狼钨）来阻止德国获取该战略物资的经济战策略，分析了其成功原因及对西班牙中立的影响。
During World War II the United States attempted to prevent Germany from acquiring wolfram (tungsten ore) in Spain by buying it in the open market. Preemptive buying forced the Germans to pay more for and to consume less tungsten, a material crucial for the production of machine tools and armor-piercing shells. The income provided an important incentive for Spain to remain neutral. The naval blockade and the relatively low elasticity of the supply of wolfram contributed to the success of the wolfram-buying campaign.