Market Trade in Patents and the Rise of a Class of Specialized Inventors in the 19th-Century United States by Naomi R. Lamoreaux and Kenneth L. Sokoloff. Published in volume 91, issue 2, pages 39-44 of American Economic Review, May 2001

A two-sector model is used to explore the role of the agricultural sector in the process of industrialization. Our hypothesis is that areas industrialize earlier where the wages for females and children relative to those for adult males are initially low. Furthermore, the lower this relative productivity of females and children in the pre-industrial economy, the proportionately more will their relative wages increase, and the higher will be the ratio of manufactured to agricultural goods. The model is used to interpret the conditions that fostered the rapid industrialization of the American Northeast, but not the South, from 1820 to 1850.

Institutions and Democratic Invention in 19th-Century America: Evidence from "Great Inventors," 1790-1930 by Zorina Khan and Kenneth L. Sokoloff. Published in volume 94, issue 2, pages 395-401 of American Economic Review, May 2004