@article{playfair_1879, 
  title={THE STUDY OF MIDWIFERY.}, 
  volume={113}, 
  DOI={10.1016/s0140-6736(02)45956-9}, 
  number={2899}, 
  publisher={Elsevier BV}, 
  author={PLAYFAIR}, 
  year={1879}
  }