@article{p. valenzuela2003contribution,
  title={The contribution of the CEA marker to CA 15.3  in the follow-up of breast cancer},
  author={p. valenzuela,s. mateos,e. tello,m. j. lopez-bueno,n. garrido,m. j. gaspar},
  journal={European Journal of Gynaecological Oncology},
  volume={24},
  number={1},
  pages={60--62},
  doi = {10.12892/ejgo20030160},
  year={2003}
}