[1] US FDA, Tobacco Regulatory Sci Fellowship Program, Silver Spring, MD 20993 USA
[2] Georgetown Univ, Med Ctr, Lombardi Comprehens Canc Ctr, Washington, DC 20007 USA
[3] CDC, Off Smoking & Hlth, Natl Ctr Chron Dis Prevent & Hlth Promot, Atlanta, GA 30333 USA
[4] US FDA, Off Sci, Ctr Tobacco Prod, 10903 New Hampshire Ave,Bldg 71,Room G335, Silver Spring, MD 20993 USA