1. Clinical phonocardiography and external pulse recording, 3rd ed;Tavel,1978
2. Cardiac auscultation;Shaver;Curr Probl Cardiol,1995
3. Cardiac auscultation;Ronan;Heart Dis Stroke,1993
4. Bedside cardiology, 2nd ed;Constant,1976
5. Bedside cardiac diagnosis;Marriot,1991