TY  - RPRT
TI  - Computer sleep stage classification using heart rate data.
AU  - A J Welch
AU  - P C Richardson
PY  - 1973
DO  - 10.1016/0013-4694(73)90041-2
UR  - https://pubmed.ncbi.nlm.nih.gov/4119527/
ID  - 4119527
ER  -