1. Interaction terms in logit and probit models
2. American Lung Association of Texas (2003). Answers to frequent arguments against a tax increase.
3. Retrieved December 31, 2003, from http://www.texaslung.org/aboutus/newsroom/newsreleases/coalitions/texansinvestinginhealthyfamilies/041603_cigarettetaxarguments.htm.
4. A Theory of Rational Addiction
5. Campaign for Tobacco-Free Kids (2003). State cigarette tax increases benefit lower-income smokers and families.