Pathophysiologic Correlates of Thromboembolism in Nonvalvular Atrial Fibrillation: II. Dense Spontaneous Echocardiographic Contrast (The Stroke Prevention in Atrial Fibrillation [SPAF-III] Study)Richard Asinger, Jonathan L. Halperin, Lesly A. Pearce et al.|Journal of the American Society of Echocardiography|1999Cited by 120