CDC Influenza Information: http://www.cdc.gov/ncidod/diseases/flu/fluvirus.htm

National Institute of Allergy and Infectious Diseases: http://www.niaid.nih.gov

World Health Organization: http://www.who.int/health-topics/influenza.htm

FluNet: http://www.who.int/flunet

U.S. Department of Health and Human Services: http://www.dhhs.gov

American Lung Association: http://www.lungusa.org/diseases/c&fguide/lungcolds_flu.html

National Foundation for Infectious Disease: http://www.nfid.org/library/influenza

Consumer health information from sources such as John Hopkins and Harvard Medical School: http://www.intelihealth.com

ZymeTx, Inc.: http://www.fluwatch.com