Roustant, O., D. Ginsbourger, and Y. Deville. “DiceKriging, DiceOptim: Two R Packages for the Analysis of Computer Experiments by Kriging-Based Metamodeling and Optimization”. Journal of Statistical Software, vol. 51, no. 1, Oct. 2012, pp. 1-55, doi:10.18637/jss.v051.i01.