6Cockburn W C, Delon P J, Ferreira W. Origin and progress of the 1968-1969 Hong Kong influenza epidemic[J]. Bull World Health Organ,1969, 41:345-348.
7Kawaoka Y, Krauss S, Webster R G. Avianto-human transmission of the PB1 gene of influenza A viruses in the 1957 and 1968 pandemics[J]. J Virol,1989,63(11).4603-4608.
8Viboud C, Grais R F, Lafont B A, et al. Multinational impact of the 1968 Hong Kong pandemic : evidence for a smoldering pandemic[J].J Infect Dis, 2005,192 :223-248.
9Kilbourne E D. Influenza pandemics of the 20th century[J]. Emerg Infect Dis, 2006,12 (1). 9-14.
10History of pandemics Influenza pandemics of the twentieth century[EB/OL], http://www.hpa. org. uk/webw/HPAweb&HPAwebStandard/HPAweb_C/11957337779607 p=1191942171185.