Physical distancing interventions and incidence of coronavirus disease 2019: natural experiment in 149 countries.
Islam N, Sharp SJ, Chowell G, Shabnam S, Kawachi I, Lacey B, Massaro JM, D'Agostino RB, White M. Physical distancing interventions and incidence of coronavirus disease 2019: natural experiment in 149 countries. BMJ. 2020 07 15; 370:m2743.