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. 2018 Oct 2;20(10):e10175. doi: 10.2196/10175

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©Samantha R Paige, Michael Stellefson, Janice L Krieger, Charkarra Anderson-Lewis, JeeWon Cheong, Christine Stopka. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 02.10.2018.

This is an open-access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work, first published in the Journal of Medical Internet Research, is properly cited. The complete bibliographic information, a link to the original publication on http://www.jmir.org/, as well as this copyright and license information must be included.

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Literature extraction procedures. The asterisk indicates that Phase 3 N values exceed the total sample of 27 as some articles included both definitions and models or measures.