Edgeworth, K. E., Longford, F. P., Keynes, J. M., & O'Brien, G. (1934). Letters from K.E. Edgeworth to The Economist, Lord Longford, Lord Keynes; an essay by Edgeworth entitled The problem of unemployment; Edgeworth's notes on David Ricardo's Principles of Political Economy, ed. by E.C.K. Gonner; presentation copy to George O'Brien of Edgeworth's Unemployment Can Be Cured. Dublin: Eason, [1944].

Edgeworth, Kenneth Essex, et al. Letters from K.E. Edgeworth to The Economist, Lord Longford, Lord Keynes; an Essay by Edgeworth Entitled The Problem of Unemployment; Edgeworth's Notes on David Ricardo's Principles of Political Economy, Ed. by E.C.K. Gonner; Presentation Copy to George O'Brien of Edgeworth's Unemployment Can Be Cured. Dublin: Eason, [1944]. 1934.