BARKER, WH. Impact of epidemic type A ihfluenza in a defined adult poplation. Am J Epidemiol. 1980, 112, 798-813
BARKER, WH. Express pneumonia and influenza associated hospitalization during influenza epidemics in the Unaited Stats. Am J Public Health. 1986, 76, 761-765
Center for Disease Control. Prevention and control of influenza :part 1, Vaccine-recommendations of the Advisory Communittee on Immunization Practices (ACIP). MMWR. 1997, 46, RR-9, 1-25