@article{&na;_2003, 
  title={Continuous Epidural Infusion of 0.05% Bupivacaine Plus Hydromorphone for Labor Analgesia: An Observational Assessment in 1,830 Parturients}, 
  volume={47}, 
  DOI={10.1097/00132586-200306000-00021}, 
  publisher={Ovid Technologies (Wolters Kluwer Health)}, 
  author={&NA;}, 
  year={2003}
  }