An amino acid polymorphism in histidine-rich glyco-protein (HRG) explains 59% of the variance in plasma HRG levels - Hennis, BC; Boomsma, DI; van Boheemen, PA; Engesser, L; Kievit, P; Dooijewaard, G; Kluft, C (Thromb Haemost, 1995)