@article{x.s. liu2017site,
  title={Placental site trophoblastic tumor in early stage: a case report},
  author={j.c. nie,g.h. chen,a.q. yan,x.s. liu},
  journal={European Journal of Gynaecological Oncology},
  volume={38},
  number={3},
  pages={479--481},
  doi = {10.12892/ejgo4036.2017},
  year={2017}
}