Sarrias, Mauricio, and Ricardo Daziano. “Multinomial Logit Models With Continuous and Discrete Individual Heterogeneity in R: The Gmnl Package”. Journal of Statistical Software 79, no. 2 (July 13, 2017): 1–46. Accessed April 25, 2024. https://www.jstatsoft.org/index.php/jss/article/view/v079i02.