School closures, mortality, and human capital : evidence from the universe of closures during the 1918 pandemic in Sweden / Christian M. Dahl (University of Southern Denmark), Casper W. Hansen (University of Copenhagen and CEPR), Peter S. Jensen (Linnaeus University and IZA), Martin Karlsson (University of Duisburg-Essen and IZA), Daniel Kühnle (University of Duisburg-Essen and IZA) ; IZA Institute of Labor Economics