title: Nicotine replacement therapy: evidence from observational studies versus clinical trials.
authors.forename: Johnson
authors.initials: J
authors.lastname: George
mesh_terms: D001521:Behavior Therapy / Q000379:methods*; D009538:Nicotine / Q000008:administration & dosage*; D018722:Nicotinic Agonists / Q000008:administration & dosage*; D016032:Randomized Controlled Trials as Topic / Q000379:methods*; D016540:Smoking Cessation / Q000379:methods*; D016896:Treatment Outcome
chemical_list: D018722:Nicotinic Agonists; D009538:Nicotine