WASET
    Alexander Y. Vaninsky,  Interstate Comparison of Environmental Performance using Stochastic Frontier Analysis: The United States Case Study.   journal   = {International Journal of Economics and Management Engineering}, [online]. World Academy of Science, Engineering and Technology.
    June 2010, vol. 42(6). 596 - 600
    [viewed 20 April 2024]. Available from: https://publications.waset.org/pdf/2149.