Three distinct candidate point mutations of the von Willebrand factor gene in four patients with type IIA von Willebrand disease - Sugiura, I; Matsushita, T; Tanimoto, M; Takahashi, I; Yamazaki, T; Yamamoto, K; Takamatsu, J; Kamiya, T; Saito, H (Thromb Haemost, 1992)