1. Akerlof, G. A., ?Labor Contracts as Partial Gift Exchange?, Quarterly Journal of Economics, 1982, 97, pp. 543?569.
2. Albaek, K., Arai, M., Asplund, R., Barth, E., Strøjer Madsen, E., ?Inter-Industry Wage Differentials in the Nordic Countries?, in Westergaard-Nielsen, N. (Ed.), Wage Differentials in the Nordic Countries, North-Holland, Amsterdam, 1993 (forthcoming)
3. Arai, M., ?Industry Wage Premiums and Efficiency Wages: A Study of the Industry Wage Structure in Sweden?, University of Stockholm, Swedish Institute for Social Research, Dissertation Series, 1990, (15).
4. Barth, E., ?Why Do Some Firms Pay More??, University of California, Berkeley, Institute for Industrial Relations, Working Paper, 1992, (43).
5. Blanchflower, D. G., Freeman, R. B., ?Unionism in the United States and Other Advanced OECD Countries?, Industrial Relations, 1992, 31, pp. 56?79.