[1] NIDA, Nicotine Psychopharmacol Sect, Clin Pharmacol & Therapeut Branch, Intramural Res Program,NIH,Dept Hlth & Human Serv, Baltimore, MD 21224 USA
[2] Wake Forest Univ, Dept Psychol, Winston Salem, NC 27109 USA
[3] Virginia Commonwealth Univ, Dept Psychol, Richmond, VA 23284 USA
[4] Virginia Commonwealth Univ, Inst Drug & Alcohol Studies, Richmond, VA 23284 USA