PT - JOURNAL ARTICLE AU - C Callard TI - Tobacco control: comparative politics in the United States and Canada AID - 10.1136/tc.12.4.436 DP - 2003 Dec 01 TA - Tobacco Control PG - 436--436 VI - 12 IP - 4 4099 - http://tobaccocontrol.bmj.com/content/12/4/436.short 4100 - http://tobaccocontrol.bmj.com/content/12/4/436.full SO - Tob Control2003 Dec 01; 12