https://towardsdatascience.com/create-predictive-models-in-r-with-caret-12baf9941236
https://www.brookings.edu/blog/brown-center-chalkboard/2021/09/28/flipped-learning-what-is-it-and-when-is-it-effective/?utm_campaign=Brookings%20Brief&utm_medium=email&utm_content=167047667&utm_source=hs_email
https://cepr.org/sites/default/files/news/CovidEconomics19.pdf?utm_medium=email&utm_source=govdelivery#Paper2
https://www.hamiltonproject.org/assets/files/Environmental_Facts_FINAL.pdf