1. Blanden , J. Machin , S. 2007 Recent changes in intergenerational mobility in Britain Sutton Trust http://www.suttontrust.com/public/documents/summaryintergenerationalmobility.pdf
2. Cabinet Office 2011 Opening doors, breaking barriers: a strategy for social mobility Her Majesty's Government http://www.dpm.cabinetoffice.gov.uk/sites/default/files_dpm/resources/opening-doors-breaking-barriers.pdf
3. The effect of regression to the mean in epidemiologic and clinical studies;Davis;Am. J. Epidem.,1976