Bailey, Delia, and Jonathan N. Katz. “Implementing Panel-Corrected Standard Errors in R: The Pcse Package”. Journal of Statistical Software, Code Snippets 42, no. 1 (June 14, 2011): 1–11. Accessed March 29, 2024. https://www.jstatsoft.org/index.php/jss/article/view/v042c01.