@article{Warner2011,
author = {Warner, M. and Chen, L.H. and Makuc, D.M. and Anderson, R.N.  and Miniño, A.M. },
title= {Drug poisoning deaths in the United States, 1980–2008},
year = {2011},
journal = {NCHS Data Brief },
volume = {81},
pages = {1--8},
}