Heat has larger impacts on labor in poorer areas
by A. Patrick Behrer, R. Jisung Park, Gernot Wagner, Colleen M. Golja, and David W. Keith

Papers published in Environmental Research Letters (ERP) and Environmental Research Communications (ERC)
by A. Patrick Behrer, R. Jisung Park, Gernot Wagner, Colleen M. Golja, and David W. Keith
While cheap, such an aircraft-based program would unlikely be a secret