Immunologic differentiation of classic hemophilia (factor VIII deficiency) and von Willebrand’s disease, with observations on combined deficiencies of antihemophilic factor and proaccelerin (factor V) and on acquired circulating anticoagulants against antihemophilic factor - Zimmerman, T. S; Ratnoff, O. D; Powell, A. E (Journal of Clinical Investigation, 1971)