Pradip Kundu and  Samarjit Kar and  Manoranjan Maiti,  Some Solid Transportation Models with Crisp and Rough Costs.   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    January 2013, vol. 73(1). 14 - 21
    [viewed 19 May 2022]. Available from: https://publications.waset.org/pdf/4878.