1. Yearbook of the United States Department of Agriculture, 1921;Ball,1922
2. Hard Wheats Winning Their Way;Carleton,1914
3. New Estimates of Gross National Product for the United Kingdom 1830–1914;Deane;Review of Income and Wealth,1968
4. Population, Labor Force, and Long Swings in Economic Growth: The American Experience;Easterlin,1968
5. The Nineteenth Century Corn Laws Reconsidered;Farlie;Economic History Review,1965