^Woo, Patrick C. Y.; Huang, Yi; Lau, Susanna K. P.; Yuen, Kwok-Yung. Coronavirus Genomics and Bioinformatics Analysis. Viruses. 2010-08-24, 2 (8): 1804–1820 [2022-01-27]. ISSN 1999-4915. PMC 3185738. PMID 21994708. doi:10.3390/v2081803. (原始内容存档于2022-05-07) (英语). In all members of Betacoronavirus subgroup A, a haemagglutinin esterase (HE) gene, which encodes a glycoprotein with neuraminate O-acetyl-esterase activity and the active site FGDS, is present downstream to ORF1ab and upstream to S gene (Figure 1).