Highly active and selective anticoagulants: D-Phe-Pro-Arg-H, a free tripeptide aldehyde prone to spontaneous inactivation and its stable N-methyl derivative, D-MePhe-Pro-Arg-H - Bajusz, S; Széll, E; Bagdy, D; Barabás, é; Horváth, Gy; Diószegi, M; Fittler, Z S; Szabó, A G; Juhász, A; Szilágyi, G (J Med Chem, 1990)