Binois, Mickaël, and Robert B. Gramacy. “HetGP: Heteroskedastic Gaussian Process Modeling and Sequential Design in R”. Journal of Statistical Software 98, no. 13 (July 8, 2021): 1–44. Accessed April 20, 2024. https://www.jstatsoft.org/index.php/jss/article/view/v098i13.