{"id":"W3015019026","doi":"10.7326/m20-1342","title":"Effectiveness of Surgical and Cotton Masks in Blocking SARS–CoV-2: A Controlled Comparison in 4 Patients","year":2020,"lang":"en","type":"letter","venue":"Annals of Internal Medicine","topic":"SARS-CoV-2 and COVID-19 Research","field":"Medicine","cited_by":204,"is_retracted":true,"has_abstract":true,"ca_institutions":"","funders":"","keywords":"Medicine","routes":{"ca_aff":false,"ca_fund":false,"ca_venue":false,"about_ca":true,"invisible_to_affiliation_only":true},"retraction":{"nature":"Retraction","reason":"Error in Analyses;Unreliable Data;Unreliable Results and/or Conclusions;","date":"6/2/2020 0:00","openalex_flagged":true},"screen":null}