1. The United Kingdom: labour market institutions, law and performance;Addison,1993
2. Barth, E., Naylor, R., Raaum, O., 1994. Does union density matter? Working paper, Institute for Social Research, Oslo.
3. Unionism in the United States and other advanced OECD countries;Blanchflower;Industrial Relations,1992
4. International differences in male wage inequality; institutions versus market forces;Blau;Journal of Political Economy,1996
5. The Economics of the Trade Union;Booth,1995