1. Markou, A., and Koob, G., (Eds.) (1993) Intracranial self-stimulation thresholds as a measure of reward, Vol. 2, Oxford University Press, New York.
2. Koob, G., Markou, A., Weiss, F., and Schulteis, G. (1993) Opponent process and drug dependence: Neurobiological mechanisms, Semin Neurosci 5, 351–358.
3. Volkow, N. (2009) Tobacco Addiction, in Research Report, National Institute on Drug Abuse, Rockville, MD.
4. (2009) Results from the 2008 National Survey on Drug Use and Health: National Findings Substance Abuse and Mental Health Services Administration, Rockville, MD.
5. Le Foll, B., and Goldberg, S. R. (2009) Effects of nicotine in experimental animals and humans: an update on addictive properties, Handb Exp Pharmacol, 335–367.