Krueger,Alan B, and Lawrence H. Summers, “Efficiency Wages and the Inter-Industry Wage Structure, Econometrica,56(2), 1988, 259 ‐ 93.

Baker,George P. “Incentive Contracts and Performance Measurement,” Journal ofPolitical Economy,100(3), 1991, 598‐614

Lazear,Edward P. “Pay, Performance and Productivity.” American Economic Review, 90(5),2000, 1346 – 1361.