Links
[1] http://www.drugandalcoholdependence.com/article/S0376-8716(17)30560-4/fulltext
[2] http://www.rethinkpot.org/tags/heroin
[3] http://www.rethinkpot.org/tags/addiction
[4] http://www.rethinkpot.org/tags/study-0
[5] http://stoprxdrugabuse.org/dr/sites/default/files/u2/pathway to heroine.jpg