Walker, J, Grint, D, Strongman, H, Eggo, RM, Peppa, M, Minassian, C, Mansfield, KE, Rentsch, C, Douglas, IJ, Mathur, R, Wong, A, Quint, JK, Andrews, N, Lopez-bernal, J, Scott, A, Ramsay, M, Smeeth, L and McDonald, H (2020). UK prevalence of risk factors for severe COVID-19 disease, by age and region: point prevalence estimates in 2019 and 2014, using electronic health records. [Data Collection]. London School of Hygiene & Tropical Medicine, London, United Kingdom. https://doi.org/10.17037/DATA.00001833.

Williamson, E, Walker, AJ, Bhaskaran, KJ, Bacon, S, Bates, C, Morton, CE, Curtis, HJ, Mehrkar, A, Evans, D, Inglesby, P, Cockburn, J, Mcdonald, HI, MacKenna, B, Tomlinson, L, Douglas, IJ, Rentsch, CT, Mathur, R, Wong, A, Grieve, R, Harrison, D, Forbes, H, Schultze, A, Croker, RT, Parry, J, Hester, F, Harper, S, Perera, R, Evans, S, Smeeth, L and Goldacre, B (2020). opensafely/risk-factors-research. [Data Collection]. Github. https://github.com/ebmdatalab/opensafely-risk-factors-research

Kabudula, C and Rentsch, C (2017). Point-of-contact Interactive Record Linkage (PIRL). [Data Collection]. Zenodo. https://doi.org/10.5281/zenodo.998867