Comparative analysis of mechanical and bioprosthetic valves after aortic valve replacement - Borkon, A M; Soule, L M; Baughman, K L; Aoun, H; Baumgartner, W A; Gardner, T J; Watkins, L, Jr; Gott, V L; Reitz, B A (J Thorac Cardiovasc Surg, 1987)