1. European commission DG health and consumer directorate B, unit B2 “Cosmetics and medical devices”, http://www.economie.fgov.be/nl/binaries/02-classificatiegids_COM_2_4_1_rev_9_classification_en_tcm325-45934.pdf, accessed 10/01/2017
2. U.S. Food and Drug Administration, https://www.fda.gov/MedicalDevices/ProductsandMedicalProcedures/CosmeticDevices/WrinkleFillers/ucm227749.htm, accessed 10/01/2017
3. European commission, http://ec.europa.eu/growth/sectors/medical-devices/market-surveillance_nl, accessed 24/04/2017