Please cite both the package and the original articles in your publications: Gruson H (????). “contactdata: Social Contact Matrices for 152 Countries.” R package version 1.1.0.9000, . A BibTeX entry for LaTeX users is @Misc{, title = {{contactdata}: Social Contact Matrices for 152 Countries}, author = {Hugo Gruson}, note = {R package version 1.1.0.9000}, url = {https://CRAN.R-project.org/package=contactdata}, } Prem K, Cook AR, Jit M (2017). “Projecting social contact matrices in 152 countries using contact surveys and demographic data.” _PLoS Computational Biology_, *13*(9), e1005697. doi:10.1371/journal.pcbi.1005697 . A BibTeX entry for LaTeX users is @Article{, title = {Projecting social contact matrices in 152 countries using contact surveys and demographic data}, author = {Kiesha Prem and Alex R. Cook and Mark Jit}, journal = {PLoS Computational Biology}, year = {2017}, volume = {13}, number = {9}, pages = {e1005697}, doi = {10.1371/journal.pcbi.1005697}, } Prem K, van Zandvoort K, Klepac P, Eggo RM, Davies NG, Group CCW, Cook AR, Jit M (2021). “Projecting contact matrices in 177 geographical regions: An update and comparison with empirical data for the COVID-19 era.” _PLoS Computational Biology_, *17*(7), e1009098. doi:10.1371/journal.pcbi.1009098 . A BibTeX entry for LaTeX users is @Article{, title = {Projecting contact matrices in 177 geographical regions: An update and comparison with empirical data for the COVID-19 era}, author = {Kiesha Prem and Kevin {van Zandvoort} and Petra Klepac and Rosalind M. Eggo and Nicholas G. Davies and CMMID COVID-19 Working Group and Alex R. Cook and Mark Jit}, journal = {PLoS Computational Biology}, year = {2021}, volume = {17}, number = {7}, pages = {e1009098}, doi = {10.1371/journal.pcbi.1009098}, }