Aleta, A. Martín-Corral, D. Bakker, M. A. y Piontti, A. P. Ajelli, M. Litvinova, M. Chinazzi, M. Dean, N. E. Halloran, M. E. Longini, I. M., J. Pentland, A. Vespignani, A. Moreno, Y. Moro, E. Quantifying the importance and location of SARS-CoV-2 transmission events in large metropolitan areas Proc. Natl. Acad. Sci. 10.1073/pnas.2112182119 2022 2022