3Seither R, Calhoun K, Kngighton CL, et al. Vaccination cov- erage among children in kindergarten-united states, 2014-15 school year [J]. MMWR Morb Mortal Wkly Rep, 2015, 64 (33) : 897-904.
4Allwinn R, Doerr HW. Comparison of seasonal influenza vac- cines: composition and properties [J]. Dtsch Med Wochens- chr, 2011, 136 (45): 2315-2318.