APA (7th ed.) Citation

(2020). How the first cases of COVID-19 in 10 countries become infected? a case series.

Chicago Style (17th ed.) Citation

How the First Cases of COVID-19 in 10 Countries Become Infected? a Case Series. 2020.

MLA (8th ed.) Citation

How the First Cases of COVID-19 in 10 Countries Become Infected? a Case Series. 2020.

Warning: These citations may not always be 100% accurate.