1. Pandemic influenza preparedness and response. Geneva: World Health Organization; 2009. Available from: http://www.who.int/csr/disease/influenza/pipguidance2009/en/index.html [accessed 20 April 2011].
2. WHO global influenza preparedness plan. Geneva: World Health Organization; 2005. Available from: http://www.who.int/csr/resources/publications/influenza/WHO_CDS_CSR_GIP_2005_5.pdf [accessed 20 April 2011].
3. UK influenza pandemic preparedness strategy 2011: strategy for consultation [Internet]. London: Department of Health; 2011. Available from: http://www.dh.gov.uk/en/Consultations/Liveconsultations/DH_125316 [accessed 20 April 2011].
4. The elusive definition of pandemic influenza.;Doshi;Bull World Health Organ,2011