Validity of the Empatica E4 Wristband to Measure Heart Rate Variability (HRV) Parameters: a Comparison to Electrocardiography (ECG). - Angela A. T. Schuurmans; Peter de Looff; Karin S. Nijhof; Catarina Rosada; Ron H. J. Scholte; Arne Popma; Roy Otten (J. Medical Syst., 2020)