Increases in Health-Related Workplace Absenteeism Among Workers in Essential Critical Infrastructure Occupations During the COVID-19 Pandemic - United States, March-April 2020. - Groenewold, Matthew R.; Burrer, Sherry L.; Ahmed, Faruque; Uzicanin, Amra; Free, Hannah; Luckhaupt, Sara E. (MMWR: Morbidity & Mortality Weekly Report, 2020)