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. 2018 Nov 8;8(11):e024777. doi: 10.1136/bmjopen-2018-024777

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© Author(s) (or their employer(s)) 2018. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.

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Flow diagram of included journals and research articles. AJOL, African Journals Online database; LMIC, low or middle income country.