Folmar S, Oates-Williams F, Sharp P, Reboussin D, Smith J, Cheshire K, Macer J, Potvin Klein K, Herrington D. Recruitment of participants for the Estrogen Replacement and Atherosclerosis (ERA) trial. a comparison of costs, yields, and participant characteristics from community- and hospital-based recruitment strategies. Control Clin Trials. 2001 Feb; 22(1):13-25.