. 2015 Mar 16;17(3):e68. doi: 10.2196/jmir.3414
©Uwe Sander, Martin Emmert, Jochen Dickel, Nina Meszmer, Benjamin Kolb. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 16.03.2015.
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Figure 2.
Symbols used by 7 of the 10 portals.