https://www.globalwitness.org/documents/20405/Hydrogen_is_too_expensive_-_September_2022.pdf
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://www.philadelphiafed.org/-/media/frbp/assets/community-development/discussion-papers/discussion-paper_automation.pdf
https://advances.sciencemag.org/content/advances/6/14/eaay3539.full.pdf