Bhaskaran, K, Matthews, A, Smeeth, L and Strongman, H (2019). Exposure Code List - Revascularisation (OPCS). [Data Collection]. London School of Hygiene & Tropical Medicine, London, United Kingdom. https://doi.org/10.17037/DATA.00001119.

Bidulka, P and Tomlinson, LA (2019). Procedure Codelist - End-Stage Renal Disease. [Data Collection]. London School of Hygiene & Tropical Medicine, London, United Kingdom.

Crellin, E, Mansfield, KE, Leyrat, C, Nitsch, D, Douglas, IJ, Root, A, Williamson, E, Smeeth, L and Tomlinson, LA (2017). Clinical Code List - OPCS - End stage renal disease. [Data Collection]. London School of Hygiene & Tropical Medicine, London, United Kingdom. https://doi.org/10.17037/DATA.253.

Forbes, H (2020). Clinical Code List - Moderate Immunosuppression OPCS Codes. [Data Collection]. London School of Hygiene & Tropical Medicine, London, United Kingdom. https://doi.org/10.17037/DATA.00001587.

Forbes, H (2020). Clinical Code List - Zoster Complication OPCS Codes. [Data Collection]. London School of Hygiene & Tropical Medicine, London, United Kingdom. https://doi.org/10.17037/DATA.00001599.

Silverwood, RJ, Mansfield, KE, Mulick, A, Wong, AYS, Schmidt, SAJ, Roberts, A, Smeeth, L, Abuabara, K and Langan, SM (2020). Clinical Codelist - OPCS codes for phototherapy. [Data Collection]. London School of Hygiene & Tropical Medicine, London, United Kingdom. https://doi.org/10.17037/DATA.00001977.