Boston Children’s Hospital: http://www.childrenshospital.org/health-topics/conditions/oppositional-defiant-disorder
Mayo Clinic: http://www.mayoclinic.org/diseases-conditions/oppositional-defiant-disorder/basics/definition/con-20024559
National Institute Of Health: http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002504/
Psych Central: http://psychcentral.com/disorders/oppositional-defiant-disorder-symptoms/
Web MD: http://www.webmd.com/mental-health/oppositional-defiant-disorder