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2. Centers for Disease Control and Prevention (CDC). Sexually Transmitted Diseases Surveillance. 2016 [cited 20 June 2018]. https://www.cdc.gov/std/stats16/msm.htm
3. European Centre for Disease Prevention and Control (ECDC). Data, trends, analyses: HIV and AIDS data for Europe. 2017 [cited 20 June 2018]. https://ecdc.europa.eu/en/publications-data/presentation-hivaids-surveillance-europe-2017-2016-data
4. National Institute for Public Health and the Environment. Sexually transmitted infections including HIV in the Netherlands in 2016. 2016 [cited 20 June 2018]. https://www.rivm.nl/dsresource?objectid=7b76e243-ca01-40d2-b50d-af67c2a0b83f&type=pdf&disposition=inline
5. Recreational drug use in men who have sex with men (MSM) attending UK sexual health services is significantly higher than in non-MSM;LJ Hunter;Postgrad Med J,2014