title: Nicotine replacement therapy: evidence from observational studies versus clinical trials. Comment.
authors: Simon
authors: S
authors: Chapman
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*
chemical_list: D018722:Nicotinic Agonists; D009538:Nicotine