Huu, P. N., D. N. Van, and B. P. Van. “Application of Response Surface Methodology for Evaluating Material Removal in Rate Die-Sinking EDM Roughing Using Copper Electrode”. VNUHCM Journal of Engineering and Technology, Vol. 1, no. 1, Aug. 2019, pp. 20-27, doi:https://doi.org/10.15419/stdjet.v1i1.523.