Cook, R. Dennis, Liliana M. Forzani, and Diego R. Tomassi. “LDR: A Package for Likelihood-Based Sufficient Dimension Reduction”. Journal of Statistical Software 39, no. 3 (March 1, 2011): 1–20. Accessed April 25, 2024. https://www.jstatsoft.org/index.php/jss/article/view/v039i03.