Vock, David, Marie Davidian, and Anastasios Tsiatis. “SNP_NLMM: A SAS Macro to Implement a Flexible Random Effects Density for Generalized Linear and Nonlinear Mixed Models”. Journal of Statistical Software, Code Snippets 56, no. 2 (January 25, 2014): 1–21. Accessed April 26, 2024. https://www.jstatsoft.org/index.php/jss/article/view/v056c02.