Centers for Disease Control and Prevention. National Center for Immunization and Respiratory Diseases. Possible side-effects from vaccines. http://www.cdc.gov/vaccines/vac-gen/side-effects.htm. Last updated March 31, 2016. Accessed April 2016.
Immunization Action Coalition. MMR vaccine does not cause autism: examine the evidence. http://www.immunize.org/catg.d/p4026.pdf. November 2013. Accessed April 2016.
Centers for Disease Control and Prevention. Vaccine safety: fainting (syncope). http://www.cdc.gov/vaccinesafety/concerns/fainting.html. Updated October 27, 2015. Accessed April 3, 2016.