Ray SC and K Hiung Joon (1995). “Cost Efficiency in the US Steel Industry: A Nonparametric Analysis Using Data Envelopment Analysis.” EJOR 80: 654-671.
Ray SC and K Hiung Joon (1995). “Cost Efficiency in the US Steel Industry: A Nonparametric Analysis Using Data Envelopment Analysis.” EJOR 80: 654-671.