Cô vịt: Xi trong bảng chữ cái Hy Lạp

• https://www.thegatewaypundit.com/2021/11/skips-next-greek-letter-nu-naming-new-covid-variant-next-letter-xi-might-draw-attention-china-named-omicron-instead/
• https://thekylebecker.substack.com/p/pfizer-and-biontech-consider-future