1. A short history of vaccination;Plotkin,2004
2. Smallpox and Its Eradication;Fenner,1988
3. Certification of polio eradication: process and lessons learned;Smith;Bull. World Health Organ.,2004
4. National Institute of Allergy and Infectious Diseases, Understanding vaccines: what they are and how they work. http://www.niaid.nih.gov/publications/vaccine/pdf/undvacc.pdf.
5. Disease Listing, Meningococcal Disease, General Info;National Center for Infectious Diseases,2005