1. Center for Disease Control Improving nation's vision-a coordinated public health approach: technical report http://www.cdc.gov/visionhealth/pdf/improving_nations_vision_health.pdf
2. World Health Organization Fact sheet on blindness and visual impairment 2016 http://www.who.int/mediacentre/factsheets/fs282/en/
3. World Health Organization Library cataloguing-in-publication data http://www.who.int/blindness/partnerships/vision2020/en/
4. Hupp S Cognitive differences between congenitally and adventitiously blind individuals 2003 digital.library.unt.edu/ark:/67531/metadc4318/m2/dissertation.pdf
5. Knowledge of dental health and oral hygiene practices of Taiwanese visually impaired and sighted students;Chang;J Vis Impair Blind,2004