1. Immunization against diseases of public health importance. Fact Sheet No. 288;World Health Organization,2005
2. World Health Organization. Expanding immunization coverage, Available at: http://www.unicef.org/immunization/index_coverage.html [accessed April 2012].
3. World Health Organisation. Expanded Programme on Immunization, Available at: http://www.who.int/immunization_delivery/en/ [accessed April 2012].
4. GAVI Alliance website. Available at: www.gavialliance.org [accessed April 2012].
5. United Nations Children's Fund. Global Immunization Vision and Strategy 2006–2015;World Health Organization,2005