Funding for this research was provided by:
National Institute on Drug Abuse (T32DA035167)
Center for Substance Abuse Prevention (SP019436)
Text and Data Mining valid from 2019-01-14
First Online: 14 January 2019
Compliance with Ethical Standards
: The authors declare that they have no conflict of interest.
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
: For this type of study, formal consent was not required.