To cite nbTransmission:

  Leavitt SV, Lee RS, Sebastiani P, Horsburgh CR, Jenkins HE, White LF
  (2020). “Estimating the relative probability of direct transmission
  between infectious disease patients.” _International Journal of
  Epidemiology_, *49*. <https://doi.org/10.1093/ije/dyaa031>.

A BibTeX entry for LaTeX users is

  @Article{,
    title = {Estimating the relative probability of direct transmission between infectious disease patients},
    author = {Sarah V. Leavitt and Robyn S. Lee and Paola Sebastiani and C Robert Horsburgh and Helen E. Jenkins and Laura F White},
    journal = {International Journal of Epidemiology},
    url = {https://doi.org/10.1093/ije/dyaa031},
    volume = {49},
    issue = {3},
    year = {2020},
  }