Ishaq, Saima, and Ahsan Haq Satti. “Testing for Homogenous or Heterogenous Doers in Longitudinal Latent Class Regression Framework”. Empirical Economic Review 6, no. 1 (June 30, 2023): 20-46. Accessed September 12, 2024. https://ojs.umt.edu.pk/index.php/eer/article/view/1584.