13.
Helliwell, J. F., Huang, H., Wang, S., & Norton, M. (2021). World happiness, trust and deaths under COVID-19. In J. Helliwell, R. Layard, J. D. Sachs, J. E. De Neve, L. Aknin, S. Wang, & S. Paculor (Eds.), World happiness report 2021 (pp. 13–57). Sustainable Development Solutions Network.