1. Almond, Douglas, Kenneth Chay, and David Lee, "Does Low Birth Weight Matter? Evidence from the U. S. Population of Twin Births," Xerox, Department of Economics, University of California, Berkeley, August 2002.
2. Does Increasing Women's Schooling Raise the Schooling of the Next Generation?
3. Card, David, "Using Geographic Variation in College Proximity to Estimate the Return to Schooling," in Aspects of Labour Market Behavior: Essays in Honour of John Vanderkamp, L. N. Christophides, E. K. Grant, and R. Swidinsky, eds. (Toronto: University of Toronto Press, 1995), pp. 201-222.
4. - "The Causal Effect of Education on Earnings," in The Handbook of Labor Economics, Vol. 3, Orley Ashenfelter and David Card, eds. (New York: North-Holland, 2000).