M. K. Pradhan and  C. K. Biswas,  Modeling and Analysis of Process Parameters on Surface Roughness in EDM of AISI D2 Tool Steel by RSM Approach.   journal   = {International Journal of Mechanical and Mechatronics Engineering}, [online]. World Academy of Science, Engineering and Technology.
    September 2009, vol. 33(9). 1132 - 1137
    [viewed 26 September 2020]. Available from: https://publications.waset.org/pdf/9361.