Dunkler, Daniela, Meinhard Ploner, Michael Schemper, and Georg Heinze. “Weighted Cox Regression Using the R Package Coxphw”. Journal of Statistical Software 84, no. 2 (April 17, 2018): 1–26. Accessed January 29, 2022. https://www.jstatsoft.org/index.php/jss/article/view/v084i02.