1. Association of Anaesthetists of Great Britain and Ireland Anaesthesia and peri-operative care of the elderly 2001 http://www.aagbi.org/sites/default/files/careelderly01.pdf
2. Dhesi J British Geriatrics Society Good Practice Guide: peri-operative care for older patients undergoing surgery 2013 http://www.bgs.org.uk/index.php/topresources/publicationfind/goodpractice/2402-bpg-pops
3. American College of Surgeons National Surgical Quality Improvement Program/American Geriatrics Society Optimal pre-operative assessment of the geriatric surgical patient http://site.acsnsqip.org/wp-content/uploads/2011/12/ACS-NSQIP-AGS-Geriatric-2012-Guidelines.pdf
4. Royal College of Surgeons of England Emergency surgery. Standards for unscheduled surgical care 2011 http://www.rcseng.ac.uk/publications/docs/emergency-surgery-standards-for-unscheduled-care/@@download/pdffile/rcs_emergency_surgery_2011_web.pdf
5. Royal College of Surgeons of England and the Department of Health The higher risk general surgical patient. Towards improved care for a forgotten group 2011 http://www.rcseng.ac.uk/publications/docs/higher-risk-surgical-patient/@@download/pdffile/higher_risk_surgical_patient_2011_web.pdf