Bartolucci, Francesco, and Claudia Pigini. “Cquad: An R and Stata Package for Conditional Maximum Likelihood Estimation of Dynamic Binary Panel Data Models”. Journal of Statistical Software 78, no. 7 (June 9, 2017): 1–26. Accessed December 9, 2021. https://www.jstatsoft.org/index.php/jss/article/view/v078i07.