Friedman J, York H, Mokdad AH, Gakidou E. U.S. Children “Learning Online” during COVID-19 without the Internet or a Computer: Visualizing the Gradient by Race/Ethnicity and Parental Educational Attainment. Socius. 2021 Feb 17;7:2378023121992607. doi: 10.1177/2378023121992607. PMID: 34192146; PMCID: PMC7890417.