Perme, Maja Pohar, and Klemen Pavlic. “Nonparametric Relative Survival Analysis With the R Package Relsurv”. Journal of Statistical Software 87, no. 8 (November 30, 2018): 1–27. Accessed August 10, 2022. https://www.jstatsoft.org/index.php/jss/article/view/v087i08.