References
- Daraio , C. and Simar L. 2005 . Introducing environmental variables in non parametric frontier models: A probabilistic approach . Journal of Productivity Analysis , 24 ( 1 ) : 93 – 121 .
- Simar , L. and Wilson P.W. 2007 . Estimation and inference in two‐stage, semi parametric models of production processes . Journal of Econometrics , 136 ( 1 ) : 31 – 64 .