Funding for this research was provided by:
National Institute on Drug Abuse (1 R01 DA022962-01)
Received: 5 July 2017
Accepted: 29 August 2017
First Online: 7 September 2017
Ethics approval and consent to participate
: This research protocol was approved by the Thai Nguyen Center for Preventive Medicine Institutional Review Board and Johns Hopkins Institutional Review Board.
: Not applicable.
: The authors declare that they have no competing interests.
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