Haag, C., M. Höglinger, A. Moser, O. Hämmig, M. A. Puhan, and V. von Wyl. “Social Mixing and Risk Exposures for SARS-CoV-2 Infections in Elderly Persons”. Swiss Medical Weekly, vol. 150, no. 4950, Dec. 2020, p. w20416, doi:10.4414/smw.2020.20416.