Wojtyś, Magorzata, Giampiero Marra, and Rosalba Radice. “Copula Regression Spline Sample Selection Models: The R Package SemiParSampleSel”. Journal of Statistical Software 71, no. 6 (August 1, 2016): 1–66. Accessed April 26, 2024. https://www.jstatsoft.org/index.php/jss/article/view/v071i06.