T. V. Zolotarova, M. S. Brynza, and M. I. Yabluchanskiy, “FUNCTIONAL CLASSES AND CLINICAL CHARACTERISTICS OF CHRONIC HEART FAILURE IN PATIENTS WITH ATRIAL FIBRILLATION AND/OR FLUTTER AFTER RADIOFREQUENCY ABLATION”, J. V. N. Karazin Khark. Nat. Univ., Ser. Med., no. 35, pp. 72-77, 1.