Alsallakh, M., Sivakumaran, S., Kennedy, S., Vasileiou, E., Lyons, R., Robertson, C., Sheikh, A., Davies, G. & EAVE II Collaboration 2021, 'Impact of COVID-19 lockdown on the incidence and mortality of acute exacerbations of chronic obstructive pulmonary disease: national interrupted time series analyses for Scotland and Wales', BMC Medicine, 19(1), article no: 124. https://doi.org/10.1186/s12916-021-02000-w