The Agricultural Revolution in Northern Europe, 1750-1880: Nitrogen, Legumes, and Crop Productivity (Chorley, 1981) http://www.jstor.org/stable/2594840 Author(s): G. P. H. Chorley Source: The Economic History Review, New Series, Vol. 34, No. 1 (Feb., 1981), pp. 71-93 Published by: Blackwell Publishing on behalf of the Economic History Society Added on 11th November 2014