He is the author of “Labor Mobility, Market Integration, and Wage Convergence in Late Nineteenth-Century India,” Explorations in Economic History (July 1999); “Were Trade and Factor Mobility Substitutes in History?” (with Kevin O’Rourke and Jeffrey G. Williamson), in Migration: The Controversies and the Evidence, edited by R. Faini, J. de Melo, and K. Zimmerman, Cambridge University Press (1999); and more recently, “The Labor Market Impact of State-Level Anti-Discrimination Laws, 1940-1960,” Industrial and Labor Relations Review (January 2003).