1. Office for National statistics http://www.statistics.gov.uk/cci/
2. European Policy Committee 2006 110 14 http://europa.eu/epc/pdf/ageingsummary_en.pdf
3. Care Quality Commission Rates of survival after heart surgery in the UK http://heartsurgery.healthcarecommission.org.uk/Survival.aspx
4. An audit of cardiac surgery in patients aged over 70 years;Parry;Quarterly Journal of Medicine,1994