1. Adler EN, Boyce T, Chesney MA, et al. (1994). Socioeconomic status and health. The challenge of the gradient. Am Psychol 49: 15–24.
2. Barker DJP (1991). The foetal and infant origins of inequalities in health in Britain. J Public Health Med 13: 64–68.
3. Barker DJP (1998). Mothers, babies and health in later life. Edinburgh: Churchill Livingstone.
4. Bartley M (2004). Health inequality. An introduction to theories, concepts and methods. Cambridge: Blackwell Publishing Ltd.
5. Blane D (2006). The life course, the social gradient and health. In: Marmot M, Wilkinson R, eds. Social determinants of health. Oxford: Oxford University Press: 54–77.