Impact of direct mail intervention on knowledge, attitudes, and behavioral intentions regarding use of emergency medical services for symptoms of acute myocardial infarction. - Meischke H; Eisenberg MS; Schaeffer SM; Larsen MP; Henwood DK; Meischke, H; Eisenberg, M S; Schaeffer, S M; Larsen, M P; Henwood, D K (Evaluation & the Health Professions, 1994)