Trial of combined warfarin plus dipyridamol or aspirin therapy in prosthetic heart valve replacement: danger of aspirin compared with dipyridamol - Chesebro, J H; Fuster, V; Elveback, L R; McGoon, D C; Pluth, J R; Puga, F J; Wallace, R B; Danielson, G K; Orszulak, T A; Piehler, J M; Schaff, H V (Am J Cardiol, 1983)