Bacterial and fungal isolation from face masks under the COVID-19 pandemic | Scientific Reports
Respiratory virus shedding in exhaled breath and efficacy of face masks | Nature Medicine
Die beste Kindermaske im Test
Effectiveness of Face Mask or Respirator Use in Indoor Public Settings for Prevention of SARS-CoV-2 Infection — California, February–December 2021 | MMWR
KN95 Face Masks - CE Certified - 5PLY - Protective Mask — Dr Medic