Aspirin, heparin, or both to treat acute unstable angina - Theroux, P; Ouimet, H; McCans, J; Latour, J-G; Joly, P; Lévy, G; Pelletier, E; Juneau, M; Stasiak, J; de Guise, P; Pelletier, G B; Rinzler, D; Waters, D D (N Engl J Med, 1988)