CDC. https://www.cdc.gov/coronavirus/2019-ncov/travelers/when-to-delay-travel.html
Diakses pada 18 Maret 2021Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/coronavirus/in-depth/coronavirus-safe-travel-advice/art-20486965
Diakses pada 18 Maret 2021NPR. https://www.npr.org/sections/goatsandsoda/2020/10/20/925892185/do-masks-really-cut-your-risk-of-catching-covid-19-on-long-plane-flights
Diakses pada 18 Maret 2021NCBI. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7543400/
Diakses pada 18 Maret 2021