1. 2017 public transportation fact book, Washington, DC,2017
2. APTA ridership report,2018
3. Public transportation ridership rises to more than 70 percent of pre-pandemic levels,2022
4. How coronavirus is disrupting public transit;App,2020
5. The impact of COVID-19 on small business outcomes and expectations;Bartik;Proceedings of the National Academy of Sciences of the United States of America,2020