- "Covid: WHO renames UK and other variants with Greek letters". BBC News. 2021-05-31. 喺2021-06-08搵到.
- Grover, Natalie (14 June 2021). "Delta variant Covid symptoms 'include headaches, sore throat and runny nose'". The Guardian. London. 喺2021-06-30搵到.
- Roberts, Michelle (14 June 2021). "Headache and runny nose linked to Delta variant". BBC News. London. 喺2021-07-02搵到.
- Radcliffe, Shawn (14 June 2021). "The COVID-19 Delta Variant: Here's Everything You Need to Know". Healthline. 喺2021-07-02搵到.