To cite package 'seroincidence' in publications use:

Peter Teunis and Jan van Eijkeren (2018). Estimating Infection Rates from Serological Data. R package version 2.0.0.

Corresponding BibTeX entry:

  @Manual{,
    title = {seroincidence: Estimating Infection Rates from Serological
      Data},
    author = {Peter Teunis and Jan {van Eijkeren}},
    year = {2018},
    note = {R package version 2.0.0},
    url =
      {https://ecdc.europa.eu/en/publications-data/seroincidence-calculator-tool},
  }