Gullov AL, Koefoed BG, Petersen P. Bleeding during warfarin and aspirin therapy in patients with atrial fibrillation: the AFASAK 2 study. Atrial Fibrillation Aspirin and Anticoagulation. Arch Intern Med. 1999 Jun 28, 159(12), 1322-1328. [PMID]: 10386508.
Koefoed BG, Feddersen C, Gullov AL, Petersen P. Effect of fixed minidose warfarin, conventional dose warfarin and aspirin on INR and prothrombin fragment 1 + 2 in patients with atrial fibrillation. Thromb Haemost. 1997 May, 77(5), 845-848. [PMID]: 9184390.