Mutations in hemophilia Bm occur at the Arg 180-Val activation site or in the catalytic domain of factor IX - Bertina, R M; van der Linden, I K; Mannucci, P M; Reinalda-Poot, H H; Cupers, R; Poort, S R; Reitsma, P H (J Biol Chem, 1990)