von Willebrand factor synthesized by endothelial cells from a patient type IIB von Willebrand disease supports platelet adhesion normally but has an increased affinity for platelets - De, Groot PG; Federici, A B; De, Boer HC; D’Alessio, P; Mannucci, P M; Sixma, J J (Proc Natl Acad Sci USA, 1992)