@article{
  author = {Alinezhad, Alireza, Mirmozaffari, Mirpoya},
  title = {Malmquist Productivity Index Using Two-stage DEA Model in Heart Hospitals},
  journal = {Iranian Journal of Optimization},
  year = {2018},
  volume = {10},
  number = {2},
  pages = {81-92},
  doi = {}
}