1. 1. Zhang, J., Yang, W.Z., Guo, Y.J., et al. (2004): Epidemiologic characteristics of influenza in China, from 2001 to 2003. Chin. J. Epidemiol., 25, 461–465.
2. 2. Shortridge, K.F. and Stuart-Harris, C.H. (1982): An influenza epicenter? Lancet, 2, 812–813.
3. Emergence and pandemic potential of swine-origin H1N1 influenza virus
4. 4. Centers for Disease Control and Prevention (2009): Swine-origin influenza A (H1N1) virus infections in a school—New York City, April 2009. Morbid. Mortal. Wkly. Rep., 58, 470–472.
5. 5. Centers for Disease Control and Prevention (2009): Outbreak of swine-origin influenza A (H1N1) virus infection—Mexico, March–April 2009. Morbid. Mortal. Wkly. Rep., 58, 467–470.