Abnormalities of heart rate turbulence and heart rate variability as indicators of increased cardiovascular risk in patients with systemic sclerosis - Poliwczak, Adam R.; Waszczykowska, Elżbieta; Dziankowska-Bartkowiak, Bożena; Dworniak-Pryca, Katarzyna (Advances in Dermatology and Allergology/Postępy Dermatologii i Alergologii, 2019)