1. Centers for Disease Control and Prevention. Hospitalizations for Patients Aged 85 and Over in the United States, 2000–2010. Secondary Centers for Disease Control and Prevention. Hospitalizations for Patients Aged 85 and Over in the United States, 2000–2010. http://www.cdc.gov/nchs/data/databriefs/db182.htm
2. Wittenberg R , Luke S , McCormick B , et al. Centre for Health Service Economics & Organisation. Understanding emergency hospital admissions of older people. Secondary Centre for Health Service Economics & Organisation. Understanding emergency hospital admissions of older people, 2014. http://www.chseo.org.uk/downloads/report6-emergencyadmissions.pdf
3. A Data Book: Health Care Spending and the Medicare Program (June 2014). Washington DC: Medicare Payment Advisory Commission. Secondary A Data Book: Health Care Spending and the Medicare Program (June 2014). Washington DC: Medicare Payment Advisory Commission, 2014. http://www.medpac.gov/documents/publications/jun14databookentirereport.pdf
4. Preventing admission of older people to hospital;D'Souza;BMJ,2013
5. Frailty in elderly people;Clegg;Lancet,2013