@article{x.s. liu2017chemotherapy,
  title={Postoperative chemotherapy on placental site trophoblastic tumor in early stage: analysis of 60 cases},
  author={j.c. nie,g.h. chen,a.q. yan,x.s. liu},
  journal={European Journal of Gynaecological Oncology},
  volume={38},
  number={3},
  pages={431--440},
  doi = {10.12892/ejgo4035.2017},
  year={2017}
}