Maintenance of smoking cessation: effect of follow-up letters, smoking motivation, muscle tension, and health locus of control.
D000328:Adult; D001294:Attitude to Health; D005260:Female; D006801:Humans; D007389:Internal-External Control; D008297:Male; D008875:Middle Aged; D009042:Motivation; D009119:Muscle Contraction; D009126:Muscle Relaxation; D000074606:Smoking Prevention