Wongoutong, C., J. Jitthavech, and V. Lorchirachoonkul. “An Application of Nelder-Mead Algorithm in Response Surface Methodology: CCD”. Thailand Statistician, vol. 15, no. 2, July 2017, pp. 167-83, https://ph02.tci-thaijo.org/index.php/thaistat/article/view/92206.