Alvarez-Martin C, Ribera A, Marsal JR, Ariza-Sole A, Perez-Hoyos S, Oristrell G, Soriano-Colome T, Romaguera R, Pijoan JI, Lidon RM, Mauri J, Ferreira-Gonzalez I. Dynamics of emergency cardiovascular hospital admissions and in-hospital mortality during the COVID-19 pandemic: time series analysis and impact of socioeconomic factors. Front. Cardiovasc. Med. 2022 Apr 26. doi: 10.3389/fcvm.2022.827212
Groenwold R, Uddin M, Roes K, de Boer A, Rivero-Ferrer E, Martin E, Gatto N, Klungel O. Instrumental variable analysis in randomized trials with non-compliance and observational pharmacoepidemiologic studies. OA Epidemiology. 2014 May 9;2(1):9.