National Network for Immunization Information:  http://www.immunizationinfo.org/

The Vaccine Education Center at the Children's Hospital of Philadelphia:  http://www.vaccine.chop.edu/

Immunization Action Coalition (IAC):  http://www.immunize.org/

World Health Organization:  www.who.int/mediacentre/news/notes/2005/np09/en

American Academy of Pediatrics:  http://www.aap.org/

The Vaccine Page, Vaccine News and Database:  http://www.vaccine.com/

Allied Vaccine Group (AVG):  http://www.vaccine.org/

The Female Athlete Triad Coalition:  http://www.femaleathletetriad.org/