I. V. Shanina and D. E. Volkov, “FREQUENCY OF DETACHED CARDIAC DRUGS PRESCRIBING IN PATIENTS OF DIFFERENT CLASSES QRS COMPLEX DURATION ON THE PERMANENT PACING BACKGROUND”, J. V. N. Karazin Khark. Nat. Univ., Ser. Med., no. 27, pp. 33-37, Jul. 2015.