TY  - RPRT
TI  - Heart rate variability: back to the beginning.
AU  - Tomas Kara
AU  - Jiri Nykodym
AU  - Virend K Somers
PY  - 2003
DO  - 10.1046/j.1540-8167.2003.03258.x
UR  - https://pubmed.ncbi.nlm.nih.gov/12890037/
ID  - 12890037
ER  -