5 IZA Discussion Papers
IZA Discussion Paper No. 14334
IZA Discussion Paper No. 13844
IZA Discussion Paper No. 13785
IZA Discussion Paper No. 13625
IZA Discussion Paper No. 13293
published in: Nature Journal: Scientific Reports , 2021, 11, 1972, (appeared also in CEPR's: Covid Economics: Vetted and Real Time Papers, 2020, 23)