Summers, Lawrence H., 1988 " Relative Wages, Efficiency Wages, and Keynesian Unemployment," American Economic Review, American Economic Association, vor. 78(2), page 383-388, May.
Summers, Lawrence H, 1988. "Relative Wages, Efficiency Wages, and Keynesian Unemployment," American Economic Review, American Economic Association, vol. 78(2), pages 383-388, May.