Use of the collagen-binding assay for von Willebrand factor in the analysis of type 2M von Willebrand disease: a comparison with the ristocetin cofactor assay - Riddell,A.F.; Jenkins,P.V.; Nitu-Whalley,I.C.; McCraw,A.H.; Lee,C.A.; Brown,S.A. (Br J Haematol, 2002)