Internet National Center for Biotechnology Information NCBI NLM MEDLINE humans pubmed abstract nih national institutes of health national library of medicine treatment outcome research support u.s. gov't female male N.I.H. Extramural middle aged P.H.S. Clinical Trial Randomized Controlled Trial Telephone smoking cessation / methods* multivariate analysis electronic mail pmid:21330267 pmc3082503 doi:10.1093/ntr/ntq257 susan m zbikowski lisa m jack gary e swan benzazepines / administration & dosage counseling / methods* nicotinic agonists / administration & dosage quinoxalines / administration & dosage telecommunications* varenicline