1. The failed century of the child: Governing America’s young in the twentieth century;J Sealander,2003
2. Association between vaccine refusal and vaccine-preventable diseases in the United States;VK Phadke;JAMA,2016
3. Elam-Evans LD, Yankey D, Singleton JA, Kolasa M. National, state, and selected local area vaccination coverage among children aged 19–35 months—United States, 2013. In: Mobidity and mortality weekly report [Internet]. 2014. Available: https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6334a1.htm
4. “Herd immunity”: A rough guide;P Fine;Clin Infect Dis,2011
5. States with religious and philosophical exemptions from school immunization requirements [Internet]. 2016 [cited 8 Sep 2017]. Available: http://www.ncsl.org/research/health/school-immunization-exemption-state-laws.aspx