Potapenko, S. V. “Peculiarities of Heart Rhythm Variability in Children and Adolescents With Arrhythmias in the Presence of Comorbidity of the Upper Gastrointestinal Tract”. Zaporozhye мedical Journal, vol. 18, no. 3, Sept. 2016, doi:10.14739/2310-1210.2016.3.76984.