External Peer Review Quality Assurance Testing in von Willebrand Disease: The Recent Experience of the United States College of American Pathologists Proficiency Testing Program - Hayes, Timothy E; Brandt, John T; Chandler, Wayne L; Eby, Charles S; Kottke-Marchant, Kandice; Krishnan, Jayashree; Lefkowitz, Jerry B; Olson, John D; Rund, Chad R; Van Cott, Elizabeth M; Cunningham, Mark T (Seminars in Thrombosis and Hemostasis, 2006)