TY  - RPRT
TI  - Heart-rate variability.
AU  - A J Mearns
AU  - D A Brodie
AU  - G D Unsworth
PY  - 1977
DO  - 10.1016/s0140-6736(77)90042-3
UR  - https://pubmed.ncbi.nlm.nih.gov/69131/
ID  - 69131
ER  -