Use of a Thrombin Generation Assay and Thromboelastometry in the Assessment of the Efficacy of Treatment with Activated Prothrombin Complex Concentrate (APCC) or Recombinant Factor VIIa (rFVIIa) Concentrate in Patients with Acquired Haemophilia and in Patients with Haemophilia A with Inhibitor ‐ A Multicenter Study