1. Periprosthetic femoral fractures -incidence, classification problems and the proposal of a modified classification scheme;Frenzel S;Int Orthop,2015
2. NJR 17th Annual report 2019. National joint registry for England, Wales, Northern Ireland and the Isle of Man. (2019). https.//reports.njrcentre.org.uk/downloads.
3. 2017/18 and 2018/19 National Tariff Payment System. NHS England and NHS Improvement. (2019). https.//improvement.nhs.uk/documents/1044/2017-18_and_2018-19_National_Tariff_Payment_System.pdf.
4. A Simple Guide to Payment By Results. Department of Health. https.//assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/213150/PbR-Simple-Gui....
5. Ales KL, Mackenzie CR. A new method of classifying prognostic comorbidity in longitudinal studies: development and validation;Charlson ME;J Chronic Dis,1987