1. 4Q GDP: Economy expands at a 4.0% annualized rate.
2. Commercial Laboratory Seroprevalence Survey Data.
3. Hidden Outbreaks Spread Through U.S. Cities Far Earlier Than Americans Knew, Estimates Say.
4. https://github.com/adityalab/mdl-ode-missing.
5. Interim Economic Projections for 2020 and 2021.