Chen YS, Lu WA, Pagaduan JC, Kuo CD
A Novel Smartphone App for the Measurement of Ultra–Short-Term and Short-Term Heart Rate Variability: Validity and Reliability Study
JMIR Mhealth Uhealth 2020;8(7):e18761
URL: mhealth.jmir.org/2020/7/e18761
DOI: 10.2196/18761