TY  - RPRT
TI  - Heart-rate variability (CVT): concurrent validity and test-retest reliability.
AU  - J A Burdick
PY  - 1968
DO  - 10.2466/pms.1968.26.3.1001
UR  - https://pubmed.ncbi.nlm.nih.gov/5657701/
ID  - 5657701
ER  -