@techreport{Blau2020,
author = {Blau, F.D. and Koebe, J. and Meyerhofer, P.A.},
title= {Who are the essential and frontline workers?},
year = {2020},
doi = {10.3386/w27791},
publisher = {National Bureau of Economic Research},
institution = {Working Paper 27791},
}