1. World internet users and 2018 population stats.Internet World Stats https://www.internetworldstats.com/stats.htmAccessed on 14/4/2018.
2. Questionnaire Survey Nonresponse: A Comparison of Postal Mail and Internet Surveys
3. Survey monkey: a cheap and easy electronic survey tool for research and program evaluation;Collier A;J Am Acad Dermatol,2005
4. Online survey of US dermatologists’ sunscreen opinions: perceptions, recommendation factors, and self‐usage;Farberg A;J Drugs Dermatol,2016
5. Acne and cosmetics: a cross‐sectional, web‐based questionnaire survey of the views and opinions of Italian dermatologists on the use of camouflage cosmetics in female patients;Mastrolonardo M;G Ital Dermatol Venereol,2017