Freddy Hernández, Olga Cecilia, and Sebastián. “Cubm Package in R to Fit CUB Models”. Comunicaciones en Estadística 11, no. 2 (December 21, 2018): 219–238. Accessed April 1, 2025. https://revistas.usantotomas.edu.co/index.php/estadistica/article/view/3857.