Callejas, J L [The use of anticoagulation in patients with chronic nonvalvular atrial fibrillation]. [electronic resource] - Medicina clinica Nov 1999 - 679 p. digital Publication Type: Letter ISSN: 0025-7753 Subjects--Topical Terms: AgedAnticoagulants--therapeutic useAtrial Fibrillation--drug therapyChronic DiseaseHumansRetrospective Studies