White Servitude and the Growth of Black Slavery in Colonial America
研究了美国殖民时期西印度群岛和南方大陆殖民地中，从依赖白人契约劳工转向使用黑人奴隶的两步过程，并解释了这一转变与技能市场相对成本变化的关系。
The role of white servitude evolved in a similar way during the American colonial period in those West Indian and southern mainland colonies where slavery became quantitatively important. The change from primary reliance on bound white labor to the use of slaves occurred in two steps, with an initial transition from servants to slaves in unskilled field work, followed some time later by widespread training of blacks and substitution of slaves for servants in skilled occupations. The timing of the two steps can be explained as a function of the changing relative costs of indentured and slave labor in the markets for unskilled and skilled labor.