7Jeffrey R. Davis, Robert Johnson, Jan Stepnanek,et al. Fundamen- tals of aerospace medicine(Fourth edition) [M]. USA: Lippincott Williams&Wilkins,2008.
8Sharpe TW. Epidemiology of Norwalk virus during an outbreak of acute gastroenteritis aboard a US aircraft carrier[J]. Journal of Medical Virology, 1995, 45(1):61-67.
9Minooee A, Rickman LS. Infectious diseases on Cruise ships[J]. Clinical Infectious Diseases. 1999, 29(4):737-44.
10Hobson JP. Analysis of the US cruise line industry[J].Tourism Management,1993,14(6):453 -462.