Primigravid labor; a graphicostatistical analysis.

@article{Friedman1955PrimigravidLA,
  title={Primigravid labor; a graphicostatistical analysis.},
  author={Eli A. Friedman},
  journal={Obstetrics and gynecology},
  year={1955},
  volume={6 6},
  pages={567-89}
}