Delaware Health and Social Services. https://dhss.delaware.gov/dph/files/swineflumasksfaq.pdf
Diakses pada 12 Desember 2019Disease Prevention & Control. https://www.sfcdcp.org/communicable-disease/healthy-habits/how-to-put-on-and-remove-a-face-mask/
Diakses pada 12 Desember 2019Centre for Health Protection. https://www.chp.gov.hk/files/pdf/use_mask_properly.pdf
Diakses pada 12 Desember 2019Department of Health. https://www.info.gov.hk/info/sars/en/facemask.htm
Diakses pada 12 Desember 2019