@article{aigner1977,
  title={Formulation and estimation of stochastic frontier production function models},
  author={Dennis J. Aigner and C. A. Knox Lovell and Peter Schmidt},
  year={1977},
  journal={Journal of Econometrics},
  doi={10.1016/0304-4076(77)90052-5},
  url={https://doi.org/10.1016/0304-4076(77)90052-5}
}