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. 2020 Aug 13;22(8):e18350. doi: 10.2196/18350

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©Tareq Nasralah, Omar El-Gayar, Yong Wang. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 13.08.2020.

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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Opioid drug abuse ontology tree hierarchy that reflects the distribution of sample tweets over the ontology concepts and terms. Rx: prescription.