Kotlar Velkova, Irina, et al. “QT PROLONGATION AND VENTRICULAR ARRHYTHMIA IN METHADONE USER PRESENTING WITH SEVERE HYPOKALEMIA”. KNOWLEDGE - International Journal , vol. 55, no. 4, Dec. 2022, pp. 539-44, http://ikm.mk/ojs/index.php/kij/article/view/5854.